KR101483807B1 - Cellulose ester optical film, polarizing plate and liquid crystal display using the cellulose ester optical film, and method for producing cellulose ester optical film - Google Patents

Abstract

A cellulose ester optical film comprising a cellulose ester, a polymer of the following (a) and a compound of the following (b): (a) an ethylenically unsaturated monomer having a partial structure represented by the following formula (B) at least one compound selected from the group consisting of a carbon radical scavenger, a phenol-based compound and a phosphorus-based compound.

≪ Formula 1 >

(Wherein R ¹ , R ² and R ³ each independently represent an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and R ¹ , R ² and R Two arbitrary ^three of them may combine with each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded)

Cellulose ester optical film, retardation, ethylenically unsaturated monomer, carbon radical scavenger, phenol compound, phosphorus compound

Description

TECHNICAL FIELD [0001] The present invention relates to a cellulose ester optical film, a polarizing plate and a liquid crystal display using the cellulose ester optical film, and a process for producing a cellulose ester optical film. ESTER OPTICAL FILM}

The present invention relates to a cellulose ester optical film, a polarizing plate using the cellulose ester optical film, a liquid crystal display device, and a process for producing a cellulose ester optical film.

The liquid crystal display (LCD) is widely adopted as a display device for a word processor, a personal computer, a television, a monitor, a portable information terminal or the like because it can be directly connected to an IC circuit with low voltage and low power consumption and can be made particularly thin have. The basic configuration of this LCD is, for example, a polarizing plate provided on both sides of a liquid crystal cell.

However, the polarizing plate allows only light of a polarization plane in a certain direction to pass through. Therefore, the LCD plays an important role in visualizing the change of the orientation of the liquid crystal by the electric field. That is, the performance of the LCD largely depends on the performance of the polarizing plate.

The polarizer of the polarizing plate is one in which iodine or the like is adsorbed and stretched on a polymer film. That is, a solution called H ink containing a dichroic substance (iodine) is wet-adsorbed on a film of polyvinyl alcohol, and the film is uniaxially stretched to orient the dichroic substance in one direction. As the protective film of the polarizing plate, cellulose esters, particularly cellulose triacetate, are widely used.

The cellulose ester film is widely used because it is useful as a protective film for a polarizing plate optically and physically. However, since the current film production method is a production method by a flexible film formation method using a halogen-based solvent, the cost required for solvent recovery is very large. In addition, halogen-based solvents have a problem of large environmental load. In recent years, for example, in Patent Document 1, an attempt has been made to melt-form a cellulose ester as a protective film for a polarizing plate. Since a cellulose ester is a polymer having a very high viscosity at the time of melting and also has a high glass transition temperature, Is difficult to level even after casting on a cooling drum or a cooling belt and solidified in a short period of time after extrusion. Therefore, it is difficult to obtain flatness and dimensional stability as well as dimensional stability and birefringence uniformity, Direction of birefringence uniformity is lower than that of the solution flexible film. These drawbacks, particularly when assembled in a large-sized liquid crystal display device of 15 inches or more, are required to be improved as a cause of occurrence of contrast reduction and display unevenness. Further, since the melt film is a high-temperature process exceeding 150 캜, there is also a serious problem in the cellulose ester film that the processing stability due to the thermal decomposition of the cellulose ester is degraded, and the generation and coloring of foreign objects observed using polarized light . In particular, it is difficult to improve the generation of foreign objects and the coloration of the end portions in the width direction. When a wide-width cellulose ester film is effectively formed by knurling applied to both ends of the wide-width cellulose ester film and an end portion (also referred to as an ear portion) generated when slitting the wide width disc with a prescribed width, the coloring of the end portion is remarkable It can not be used as a recycle material and can not be discarded. Therefore, the coloring of the end portion is particularly required to be improved.

Therefore, it is known to use a plasticizer for the purpose of improving processing stability of a cellulose ester. Among them, a polymer or copolymer of a vinyl monomer having an amide bond as a plasticizer having excellent flexibility, nonvolatility and non-planarity is disclosed See, for example, Patent Document 2 below). However, it has been found that when the method of Patent Document 2 is applied to a melt film, a significant problem is not solved in the optical film that the coloring is remarkable.

On the other hand, techniques for containing a phenol-based deterioration inhibitor, a thioether compound, a phosphorus compound and the like have been disclosed in order to suppress thermal deterioration in a melt film of a cellulose ester (see Patent Documents 3 and 4, for example) .

However, in any known technique, improvement in processing stability, birefringence uniformity, occurrence of foreign objects, and coloring is not sufficient. Particularly, birefringence uniformity in the film width direction, generation of foreign matter, The improvement in the current situation was inadequate.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-352620

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-212224

Patent Document 3: Japanese Patent Application Laid-Open No. 2006-241428

Patent Document 4: JP-A-2006-251746

DISCLOSURE OF THE INVENTION <

An object of the present invention is to provide a cellulose ester optical film having excellent optical properties such as small variation in retardation in the width direction and suppressing the generation of foreign matter and having little coloring at the end portion in the film width direction, A polarizing plate and a liquid crystal display using an optical film, and a method for producing a cellulose ester optical film in which the production load, equipment load and environmental load accompanying drying and recovery of a solvent are reduced.

One aspect of the present invention for achieving the above object is a cellulose ester optical film characterized by containing a cellulose ester, a polymer of the following (a), and a compound of the following (b): (a) A polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the formula (1) and at least one ethylenically unsaturated monomer, (b) at least one member selected from the group consisting of a carbon radical scavenger, a phenol compound and a phosphorus compound compound:

(Wherein R ¹ , R ² and R ³ each independently represent an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and R ¹ , R ² and R Any two of the ^{three may} be bonded to each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded)

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic flow sheet showing an embodiment of an apparatus for carrying out the method for producing a cellulose ester optical film of the present invention. Fig.

2 is an enlarged flow sheet of a main part of the manufacturing apparatus of Fig.

Fig. 3 (a) is an outline view showing an example of a main portion of a flexible die, and Fig. 3 (b) is a sectional view showing an example of a main portion of a flexible die.

4 is a sectional view of the first embodiment of the tightening rotor;

5 is a cross-sectional view in a plane perpendicular to the rotation axis of the second embodiment of the narrowing-down rotary body.

6 is a cross-sectional view in a plane including the rotating shaft of the second embodiment of the narrowing-down rotary body.

7 is an exploded perspective view schematically showing a configuration diagram of a liquid crystal display device.

The above object of the present invention can be achieved by the following arrangement.

1. A cellulose ester optical film characterized by containing a cellulose ester, a polymer (a), and a compound (b).

(a): A polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the following formula (1) in the molecule with at least one ethylenic unsaturated monomer.

&Lt; Formula 1 >

(Wherein R ¹ , R ² and R ³ each independently represent an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and R ¹ , R ² and R ³ May be bonded to each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded)

(b): at least one compound selected from the group consisting of a carbon radical scavenger, a phenol compound and a phosphorus compound.

2. The cellulose ester optical film as described in 1 above, wherein the polymer (a) has a weight average molecular weight of 1000 to 70,000.

Wherein the ethylenically unsaturated monomer having a partial structure represented by the formula (1) in the molecule is selected from the group consisting of N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylpiperidone, N-vinylcaprolactam, The cellulose ester optical film according to 1 or 2,

4. The cellulose ester optical film according to any one of 1 to 3 above, wherein the cellulose ester is a cellulose ester satisfying the substitution degree of the following formulas (1) to (3).

<Formula 1>

2.4? A + B? 3.0

<Formula 2>

0? A? 2.4

<Formula 3>

0.1? B <3.0

(Wherein A represents the substitution degree of the acetyl group and B represents the sum of the degree of substitution of the acyl group having 3 to 5 carbon atoms)

5. The cellulose ester optical film according to any one of 1 to 4, wherein the carbon radical scavenger is a compound represented by the following formula (2).

(Wherein R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ¹² and R ¹³ each independently represent an alkyl group having 1 to 8 carbon atoms)

6. The cellulose ester optical film according to any one of 1 to 4, wherein the carbon radical scavenger is a compound represented by the following formula (3).

(Wherein R ²² to R ²⁶ each independently represent a hydrogen atom, an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, n represents 1 or 2, When n is 1, R ²¹ represents an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and when n is 2, R ²¹ represents a divalent linking group.

7. The cellulose ester optical film according to any one of the items 1 to 6, wherein the phosphorus compound is a phosphonite compound represented by the following general formula (4) or (5).

R ³¹ P (OR ³² ) ₂

(Wherein R ³¹ represents a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² may combine with each other to form a ring)

(R ³⁴ O) ₂ PR ³³ -R ³³ P (OR ³⁴ ) ₂

(Wherein R ³³ represents a phenylene group which may have a substituent or a thienylene group which may have a substituent, R ³⁴ represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, A plurality of R &lt; ³⁴ &gt; may combine with each other to form a ring)

Wherein R ³⁴ in the above formula (5) is a substituted phenyl group having a substituent having a total of 9 to 14 carbon atoms with respect to one phenyl group (provided that a plurality of Lt; 7 &gt; may have a substituent).

9. The method according to item 8, wherein the phosphonate compound represented by the formula 5 is tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene diphosphonite The disclosed cellulose ester optical film.

10. A process for producing a cellulose ester as described in 1 above, wherein the carbon radical scavenger is contained in an amount of 0.1 to 1.0 part by mass, 0.2 to 2.0 parts by mass of the phenol compound, and 0.1 to 1.0 part by mass of the phosphorus compound, To (9). &Lt; / RTI &gt;

11. The cellulose ester optical film according to any one of the items 1 to 10, wherein at least one ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid is contained.

12. The cellulose ester optical film according to any one of 1 to 11 above, wherein at least one ultraviolet absorber is contained.

13. The cellulose ester optical film according to any one of items 1 to 12, wherein at least one fine particle is contained.

14. A polarizing plate characterized by using the cellulose ester optical film according to any one of 1 to 13 above.

15. A liquid crystal display device characterized by using the cellulose ester optical film according to any one of the items 1 to 13 or the polarizing plate according to 14. above.

16. A process for producing a cellulose ester optical film characterized by containing a cellulose ester, a polymer of the following (a), and a compound of the following (b)

(a): A polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the following formula (1) in a molecule with at least one ethylenically unsaturated monomer.

&Lt; Formula 1 >

(Wherein, R ^1, R ² and R ³ are each independently an aliphatic group which may have a substituent, represents a heterocyclic group which may have an aromatic group, or a substituent which may have a substituent, and, R ^1, R ^2, and Any two of R &lt; ³ &gt; may be bonded to each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded)

(b): at least one compound selected from the group consisting of a carbon radical scavenger, a phenol compound and a phosphorus compound.

17. The process for producing a cellulose ester optical film as described in 16 above, wherein the yellow index (Yc) at the center portion of the film after melt extrusion and the yellow index (Ye) at the film end satisfy the following formula (4).

<Formula 4>

1.0? Ye / Yc? 5.0

18. The method for producing a cellulose ester optical film as described in 16 or 17 above, which further comprises a step of stretching the cellulose ester film after melt extrusion in 1.0 to 4.0 times in one direction and 1.01 to 4.0 times in the direction perpendicular thereto.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited to these.

The cellulose ester optical film is produced mainly by two methods. The solution casting method, which is one of them, is a method of forming a film by softening a solution in which a cellulose ester is dissolved in a solvent and evaporating and drying the solvent. The equipment investment and manufacturing cost for the production line such as the drying line, the drying energy, and the recovery and regeneration apparatus of the evaporated solvent have become enormous, and it has become an important issue to reduce these. On the other hand, in the film formation by the melt softening method, since the solvent for adjusting the solution of the cellulose ester as the solution solution is not used, the above-mentioned drying load and facility load do not occur. Therefore, in the present invention, the melt-softening method is more preferably used than the solution-casting method.

As a result of intensive studies, the present inventors have found that, by mixing a polymer having an amide structure specific to a cellulose ester with at least one compound selected from the group consisting of a carbon radical scavenger, a phenol compound and a phosphorus compound, The uniformity of the retardation is remarkably improved. At the same time, it was also found that the coloring of the end portion in the film width direction at the time of melt film formation can be improved, and further, the generation of foreign objects can be reduced. By these effects, it was found that a cellulose ester optical film having properties equal to or higher than those produced by the solution casting method can also be obtained by a melt film-forming method.

Hereinafter, various compounds used in the present invention will be described in detail.

(Polymer of (a) above)

The cellulose ester optical film of the present invention contains at least one polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the following formula (1) and at least one ethylenically unsaturated monomer in the molecule.

&Lt; Formula 1 >

In the formula (1), R ¹ , R ² and R ³ each independently represent an aliphatic group which may have a substituent, an aromatic group which may have a substituent and a heterocyclic group which may have a substituent. Two of R ¹ , R ² and R ^{3 may} be bonded to each other to form a cyclic structure with the nitrogen atom or the nitrogen atom and the carbon atom to which they are bonded. The aromatic group which may have a substituent, the aromatic group which may have a substituent and the heterocyclic group which may have a substituent represented by R ¹ , R ² and R ³ are not particularly limited and include, for example, For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group and a trifluoromethyl group), a cycloalkyl group (for example, a cyclopentyl group, (For example, a methyl group, an ethyl group, etc.), an aryl group (e.g., a phenyl group, a naphthyl group, etc.) (For example, a vinyl group, a 2-propenyl group, a 3-butenyl group, a 1-methyl-3-propenyl group, a 3-propenyl group, Methyl-3-butenyl group, 4-hexenyl group, cyclohexenyl group and the like), a halogen atom (for example, a fluorine atom (Such as a chlorine atom, a bromine atom and an iodine atom), an alkynyl group (e.g., a propargyl group), a heterocyclic group (e.g., a pyridyl group, a thiazolyl group, an oxazolyl group, , An alkylsulfonyl group (e.g., methylsulfonyl group, ethylsulfonyl group and the like), an arylsulfonyl group (e.g., phenylsulfonyl group and naphthylsulfonyl group), an alkylsulfinyl group ), An arylsulfinyl group (e.g., phenylsulfinyl group and the like), a phosphono group, an acyl group (e.g., an acetyl group, a pivaloyl group and a benzoyl group), a carbamoyl group (Such as methylaminocarbonyl, dimethylaminocarbonyl, butylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl and 2-pyridylaminocarbonyl), a sulfamoyl group (for example, an aminosulfonyl group, a methylaminosulfonyl group, Butyl, A sulfonamido group (e.g., a methanesulfonyl group, an isopropylsulfonyl group, an isobutylsulfonyl group, a cyclopentylsulfonyl group, a cyclopentylsulfonyl group, a cyclopentylsulfonyl group, (For example, a methoxy group, an ethoxy group, a propoxy group, etc.), an aryloxy group (e.g., phenoxy, naphthyl, (E.g., acetyloxy group, benzoyloxy group, etc.), a sulfonic acid group, a salt of a sulfonic acid, an aminocarbonyloxy group, an amino group (for example, , An amino group, an ethylamino group, a dimethylamine group, a butylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, a dodecylamino group and the like), an anilino group (for example, phenylamino group, chlorophenylamino group, Siddinogi, (For example, a methyl group, an ethyl group, an ethyl group, a butyl group, a butyl group, a butyl group, a butyl group, (E.g., methoxycarbonylamino group, phenoxycarbonylamino group and the like), alkoxycarbonyl group (e.g., methoxycarbonyl group, methoxycarbonyl group, and methoxycarbonyl group) (E.g., phenoxycarbonyl group), a heterocyclic thio group, a thioureido group, a carboxyl group, a salt of a carboxylic acid, a hydroxyl group, a mercapto group, Nitro group, and the like. These substituents may be substituted by the same substituent.

In the present invention, R ¹ , R ² and R ³ Are bonded to each other to form a cyclic structure of 5 to 7 membered to be a nitrogen atom or a nitrogen atom and a carbon atom bonded to each other to form a cyclic structure. In this case, the ring may be a nitrogen atom, a sulfur May further have an atom or an oxygen atom, and may be a saturated or unsaturated monocyclic, polycyclic or condensed cyclic group. Specific examples include heterocyclic rings such as pyrrolidine ring, piperidine ring, piperazine ring, pyrrole ring, morpholine ring, thiamorpholine ring, imidazole ring, pyrazole ring, pyrrolidine ring and piperidone And these rings may be further substituted by a substituent which may further have a group represented by R ¹ , R ² and R ³ .

In the present invention, the ethylenically unsaturated monomer having a partial structure represented by the above formula (1) in the molecule has an ethylenic unsaturated bond in the molecule. At least one of the groups represented by R ¹ , R ² and R ³ is an ethylene Means an alkenyl group as a group having an unsaturated bond or at least one of the groups represented by R ¹ , R ² and R ³ has an ethylenically unsaturated bond as a partial structure. Specific examples of the ethylenically unsaturated bond include a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a styryl group, an acrylamide group, a methacrylamide group, a vinyl cyanide group, a 2-cyanoacryloxy group, , A 2-epoxy group, a vinylbenzyl group, a vinyl ether group and the like. Of these, a vinyl group, an acryloyl group, a methacryloyl group, an acrylamide group and a methacrylamide group are preferable.

Specific preferred examples of the ethylenically unsaturated monomer having the partial structure represented by the above formula (1) in the molecule used in the present invention are illustrated below, but are not limited thereto.

The ethylenically unsaturated monomers having a partial structure represented by the formula (1) in the molecule can be used singly or in combination of two or more kinds. Particularly preferred are N-vinylpyrrolidone, N-acryloylmorpholine, N -Vinylpiperidone, N-vinylcaprolactam, or mixtures thereof.

The ethylenically unsaturated monomer having a partial structure represented by the above formula (1) in the molecule used in the present invention is commercially available or can be synthesized by reference to known literature.

The ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated monomer having the partial structure represented by the formula (1) in the molecule may be an ethylenically unsaturated monomer having a partial structure represented by the formula (1) For example, methacrylic acid and its ester derivatives (such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, Ethylhexyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, dimethylamine ethyl methacrylate, diethylamino methacrylate Ethyl), acrylic acid and its ester derivatives (such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, i-butyl acrylate, Butyl acrylate, octyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethoxyethyl acrylate, diethylene glycol ethacrylate acrylate, 3-methoxybutyl acrylate (Methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether and the like), alkyl vinyl esters (vinyl formate, vinyl acetate, vinyl butyrate, caproic acid Vinyl stearate, etc.), styrene derivatives (e.g., styrene,? -Methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinylnaphthalene), crotonic acid, maleic acid, fumaric acid, Unsaturated compounds such as itaconic acid, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide and the like have. These may be copolymerized with an ethylenically unsaturated monomer having a partial structure represented by the general formula (1) in the molecule, alone or in admixture of two or more.

These ethylenically unsaturated monomers include acrylic acid esters or methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, Methyl styrene, o-methyl styrene, m-methyl styrene, isobutyl vinyl ether, and the like), alkyl vinyl esters (vinyl formate, vinyl acetate, vinyl butyrate, vinyl caprate, vinyl stearate and the like) p-methylstyrene, vinylnaphthalene, etc.).

The weight average molecular weight of the copolymer (a) used in the present invention is preferably in the range of 1,000 to 70,000. Particularly preferably in the range of 2000 to 50,000. When the weight-average molecular weight is less than 1000, there is a tendency to flow to the surface of the film. When the weight-average molecular weight is more than 70000, compatibility with the resin tends to deteriorate. The ratio of the weight average molecular weight (Mw) / number average molecular weight (Mn) of the copolymer of (a) is preferably 1.5 to 4.0, particularly preferably 1.5 to 3.0.

The proportion of the ethylenically unsaturated monomer having a partial structure represented by the above-described formula (1) in the molecule of the copolymer (a) used in the present invention is not particularly limited so long as the compatibility of the resulting copolymer with the transparent resin, It is selected considering the effect on mechanical strength. Preferably, the copolymer is blended in an amount of 10 to 80 mass%, more preferably 20 to 70 mass%, of an ethylenically unsaturated monomer having a partial structure represented by the above formula (1) in the molecule.

The method of polymerizing the copolymer (a) in the present invention is not particularly limited, and conventionally known methods can be widely employed, and examples thereof include radical polymerization, anionic polymerization, and cation polymerization. Examples of the initiator of the radical polymerization method include azo compounds and peroxides, and examples thereof include azobisisobutylonitrile (AIBN), azobisisobutyl diester derivatives, benzoyl peroxide, and the like. The polymerization solvent is not particularly limited, and examples thereof include aromatic hydrocarbon solvents such as toluene and chlorobenzene, halogenated hydrocarbon solvents such as dichloroethane and chloroform, ether solvents such as tetrahydrofuran and dioxane, An amide solvent, an alcohol solvent such as methanol, an ester solvent such as methyl acetate or ethyl acetate, a ketone solvent such as acetone, cyclohexanone or methyl ethyl ketone, or a water solvent. Depending on the choice of the solvent, it is also possible to perform solution polymerization in a homogeneous system, precipitation polymerization in which the resulting polymer precipitates, and emulsion polymerization in the micellar state.

The weight average molecular weight of the copolymer can be adjusted by a known molecular weight control method. Examples of such a molecular weight control method include a method of adding a chain transfer agent such as carbon tetrachloride, lauryl mercaptan, and octyl thioglycolate. The polymerization temperature is usually from room temperature to 130 ° C, preferably from 50 to 110 ° C.

The copolymer (a) is preferably blended in a proportion of 0.1 to 50 mass%, more preferably 5 to 30 mass%, based on the cellulose ester resin forming the optical film. At this time, the haze of the optical film is not particularly limited as long as it is 1.0 or less, but preferably the haze is 0.5 or less. More preferably, the haze when the optical film is formed is 0.3 or less.

(Carbon radical scavenger)

The "carbon radical scavenger" used in the present invention means a group having a group capable of rapidly undergoing addition reaction with a carbon radical (for example, an unsaturated group such as a double bond or a triple bond) Quot; means a compound that imparts a stable product without subsequent reaction. Examples of the carbon radical scavenger include compounds having a radical polymerization ability such as groups (unsaturated groups such as (meth) acryloyl groups and aryl groups) reacting rapidly with carbon radicals in the molecule and phenolic compounds and lactone compounds, In particular, compounds represented by the following formula (2) or (3) are preferable.

(2)

In the general formula (2), R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. R ¹² and R ¹³ each independently represent an alkyl group having 1 to 8 carbon atoms and may have a branched structure or a cyclic structure even in a straight chain. R ¹² and R ¹³ are preferably a structure represented by "* -C (CH ₃ ) ₂ -R '" containing quaternary carbon (* represents a connecting site to an aromatic ring, and R'Lt; / RTI &gt; to 5 carbon atoms). R ¹² is more preferably a tert-butyl group, a tert-amyl group or a tert-octyl group. R ¹³ is more preferably a tert-butyl group or tert-amyl group. Examples of commercially available compounds represented by the above formula (1) include "Sumilizer GM, Sumilizer GS" (all trade names, products of Sumitomo Chemical Co., Ltd.). Specific examples (1-1 to 1-18) of the compound represented by the formula (2) are illustrated below, but the present invention is not limited thereto.

(3)

In the general formula (3), R ²² to R ²⁶ each independently represent a hydrogen atom or a substituent, and the substituent represented by R ²² to R ²⁶ is not particularly limited and includes, for example, an alkyl group (for example, (For example, a cyclopentyl group, a cyclohexyl group, and the like), a cycloalkyl group (e.g., a cyclopentyl group, a cyclopentyl group, (E.g., methylthio group, ethylthio group, etc.), an arylthio group (e.g., a methylthio group, an ethylthio group), an aryl group (e.g., a phenyl group or a naphthyl group), an acylamino group (Such as a phenylthio group or a naphthylthio group), an alkenyl group (e.g., a vinyl group, a 2-propenyl group, a 3-butenyl group, 1-methyl-3-butenyl group, 4-hexenyl group, cyclohexenyl group and the like), a halogen atom (Such as a chlorine atom, a bromine atom and an iodine atom), an alkynyl group (e.g., a propargyl group), a heterocyclic group (e.g., a pyridyl group, a thiazolyl group, an oxazolyl group, , An alkylsulfonyl group (e.g., methylsulfonyl group, ethylsulfonyl group and the like), an arylsulfonyl group (e.g., phenylsulfonyl group and naphthylsulfonyl group), an alkylsulfinyl group ), An arylsulfinyl group (e.g., phenylsulfinyl group and the like), a phosphono group, an acyl group (e.g., an acetyl group, a pivaloyl group and a benzoyl group), a carbamoyl group (Such as methylaminocarbonyl, dimethylaminocarbonyl, butylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl and 2-pyridylaminocarbonyl), a sulfamoyl group (for example, an aminosulfonyl group, a methylaminosulfonyl group, Nyl group, butyl group A naphthylaminosulfonyl group, a 2-pyridylaminosulfonyl group and the like), a sulfonamide group (e.g., a sulfonamido group, a sulfamoyl group, a sulfamoyl group, a sulfamoyl group, (E.g., a methoxy group, an ethoxy group, a propoxy group, etc.), an aryloxy group (for example, a phenoxy group, a methoxy group, Naphthyloxy group, etc.), heterocyclic oxy group, siloxy group, acyloxy group (for example, acetyloxy group, benzoyloxy group etc.), sulfonic acid group, salt of sulfonic acid, aminocarbonyloxy group, amino group An amino group, an ethylamino group, a dimethylamino group, a butylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, a dodecylamino group and the like), an anilino group (such as phenylamino group, chlorophenylamino group, , Naphthylamino group, 2-pyridylamino group and the like), imide group, ureido group (for example, methyl ureido group, ethyl ureido group, pentyl ureido group, cyclohexyl ureido group, octyl ureido group, dodecyl ureido group, phenyl An alkoxycarbonylamino group (e.g., methoxycarbonylamino group, phenoxycarbonylamino group, etc.), an alkoxycarbonyl group (e.g., methoxy carbonyl group such as methoxycarbonylamino group, (For example, a phenoxycarbonyl group), a heterocyclic thio group, a thioureido group, a carboxyl group, a salt of a carboxylic acid, a hydroxyl group, a mercapto group, a mercapto group, Earthenware, nitro, and the like. These substituents may be further substituted by the same substituent.

In Formula 3, n represents 1 or 2.

In Formula 3, when n is 1, R ²¹ represents a substituent, and when n is 2, R ²¹ represents a divalent linking group. When R ²¹ represents a substituent, examples of the substituent include the same groups as the substituents represented by R ²² to R ²⁶ .

When R ²¹ represents a divalent linking group, for example, an alkylene group which may have a substituent, an arylene group which may have a substituent, an oxygen atom, a nitrogen atom, a sulfur atom, or a combination of these linking groups .

In Formula 3, n is preferably 1.

Next, specific examples of the compound represented by the formula (3) in the present invention are shown, but the present invention is not limited to the following specific examples.

The above-mentioned carbon radical scavenger may be used singly or in combination of two or more kinds. The amount of the carbon radical scavenger is appropriately selected within a range not to impair the object of the present invention. The amount is usually 0.001 to 10.0 parts by mass per 100 parts by mass of the cellulose ester Preferably 0.01 to 5.0 parts by mass, and more preferably 0.1 to 1.0 part by mass.

(Phenolic compound)

The phenolic compound to be used in the present invention is preferably a 2,6-dialkylphenol derivative compound such as those described in, for example, columns 12 to 14 of the specification of U.S. Patent No. 4,839,405, The compound represented by the formula (6) is preferable.

(6)

In the formulas, R ⁴¹ , R ⁴² and R ⁴³ represent an alkyl substituent which is further substituted or unsubstituted. Specific examples of the phenol compound include n-octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, n-octadecyl 3- (3,5- butyl-4-hydroxyphenyl) -acetate, n-octadecyl 3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl 3,5- Di-t-butyl-4-hydroxyphenyl benzoate, neododecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) (3,5-di-t-butyl-4-hydroxyphenyl) propionate, ethyl α- (4-hydroxy- (4-hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl? - , 2- (n-octylthio) ethyl 3,5-di-t-butyl-4-hydroxybenzoate, 2- Phenyl acetate, 2- (n-octadecylthio) ethyl 3,5-di-t-butyl-4-hydroxyphenyl (2-hydroxyethylthio) ethyl 3,5-di-t-butyl (2-ethylhexylthio) (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2- (n-octadecylthio) ethyl 3- Di-t-butyl-4-hydroxyphenyl) propionate, stearamide N, N-bis- [ethylene 3- (3,5- , n-butylimino N, N-bis- [ethylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2- (2-stearoyloxyethylthio) Ethyl-3,5-di-t-butyl-4-hydroxybenzoate, 2- (2-stearoyloxyethylthio) ethyl 7- Propylene glycol bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], ethylene glycol bis- [3- -t-butyl-4-hydroxyphenyl) propionate], neopentyl glycol ratio (3,5-di-t-butyl-4-hydroxyphenyl) propionate], ethylene glycol bis- (3,5- (3 ', 5') - 1-n-octadecanoate-2,3-bis- (3,5- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,1,1-trimethylolethane tris- [3- Propionate], sorbitol hexa- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2-hydroxyethyl 7- 2-stearoyloxyethyl 7- (3-methyl-5-t-butyl-4-hydroxyphenyl) heptanoate, 1,6-n-hexanediol- Butyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis (3,5-di-t-butyl-4-hydroxyhydrocinnamate ). Phenolic compounds of this type are commercially available, for example, from Ciba Specialty Chemicals under the trade names "Irganox 1076 &quot;and" Irganox 1010 &quot;.

The above-mentioned phenolic compound may be used alone or in combination of two or more kinds. The amount of the phenolic compound is suitably selected within a range not to impair the object of the present invention. The amount is usually 0.001 to 10.0 parts by mass Preferably 0.05 to 5.0 parts by mass, and more preferably 0.2 to 2.0 parts by mass.

(Phosphorus compound)

As the phosphorus compound used in the present invention, conventionally known phosphorus compounds may be used. Preferably, it is a compound selected from the group consisting of phosphite, phosphonite, phosphinite or tertiary phosphane. For example, JP-A- Japanese Patent Application Laid-open No. Hei-138188, Japanese Patent Application Laid-Open No. 2005-344044, paragraphs 0022 to 0027, Japanese Patent Laid-Open No. 2004-182979, paragraphs 0023 to 0039, Japanese Patent Application Laid-Open Nos. 10-306175, Japanese Patent Application Laid-Open Nos. 2-270892, 5-202078, 5-178870, 2004-504435, Japanese Patent Application Publication No. 2004-530759, and Japanese Patent Application 2005-353229 is preferable. The preferred phosphorous compound is the phosphonite compound represented by the above formula (4) or (5).

R ³¹ represents a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent . The plurality of R ³² may combine with each other to form a ring, and R ³² is preferably a substituted phenyl group. The total number of carbon atoms of the substituent of the substituted phenyl group is preferably 9 to 14, more preferably 9 to 11.

Examples of the substituent include, but are not limited to, an alkyl group (e.g., a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, An acylamino group (e.g., an acetylamino group, a benzoylamino group, etc.), an alkyl group (e.g., an alkyl group), an aryl group (e.g., a phenyl group or a naphthyl group), a cycloalkyl group (e.g. a cyclopentyl group or a cyclohexyl group) (E.g., methylthio group, ethylthio group, etc.), arylthio group (e.g., phenylthio group, naphthylthio group, etc.), alkenyl group Methyl-3-butenyl group, 4-hexenyl group, cyclohexenyl group, etc.), a halogen atom (e.g., fluorine A bromine atom, an iodine atom, etc.), an alkynyl group (e.g., a propargyl group), a heterocyclic group (e.g., a pyridyl group, An arylsulfonyl group (e.g., a phenylsulfonyl group, a naphthylsulfonyl group, etc.), an alkylsulfonyl group (e.g., a methylsulfonyl group or an ethylsulfonyl group) , An alkylsulfinyl group (e.g., methylsulfinyl group), an arylsulfinyl group (e.g., phenylsulfinyl group), a phosphono group, an acyl group (e.g., acetyl group, pivaloyl group, , A carbamoyl group (e.g., an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a butylaminocarbonyl group, a cyclohexylaminocarbonyl group, a phenylaminocarbonyl group, a 2-pyridylaminocarbonyl group etc.), a sulfamoyl group , An aminosulfonyl group, a methylaminosulfonyl group, a dimethylaminosulfonyl group, a butylaminosulfonyl group, a hexylaminosulfonyl group, a cyclohexylaminosulfonyl group, an octylaminosulfonyl group, a dodecylaminosulfonyl group, a phenyl (E.g., a methanesulfonamide group, a benzenesulfonamide group and the like), a cyano group, an alkoxy group (for example, a methanesulfonyl group, an ethanesulfonyl group, (For example, a methoxy group, an ethoxy group, a propoxy group and the like), an aryloxy group (for example, a phenoxy group and a naphthyloxy group), a heterocyclic oxy group, a siloxy group, Benzoyloxy group and the like), a sulfonic acid group, a salt of a sulfonic acid, an aminocarbonyloxy group, an amino group (for example, an amino group, an ethylamino group, a dimethylamino group, a butylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, , An anilino group (e.g., a phenylamino group, a chlorophenylamino group, a toluidino group, an anisidino group, a naphthylamino group, a 2-pyridylamino group, etc.), an imide group, Pottery, Ethylurea Pottery, (For example, methoxycarbonylamino group (for example, methoxycarbonylamino group) such as methoxycarbonylamino group (for example, methoxycarbonyloxy group, ethoxycarbonyloxy group, An alkoxycarbonyl group (e.g., methoxycarbonyl group, ethoxycarbonyl group, phenoxycarbonyl, etc.), an aryloxycarbonyl group (e.g., phenoxycarbonyl group and the like), a heterocyclic thio group , A thioureido group, a carboxyl group, a salt of a carboxylic acid, a hydroxyl group, a mercapto group, and a nitro group. These substituents may be further substituted by the same substituent.

In the general formula (5), R ³³ represents a phenylene group which may have a substituent or a thienylene group which may have a substituent, R ³⁴ represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl Lt; / RTI &gt; The plurality of R ³⁴ may combine with each other to form a ring, and R ³⁴ is preferably a substituted phenyl group. The total number of carbon atoms of the substituent of the substituted phenyl group is preferably 9 to 14, more preferably 9 to 11. The substituent is the same as described for R ³² .

Specific examples of the phosphonate compound represented by the general formula (4) include dialkyl-phenyl phosphonites such as dimethyl-phenyl phosphonite and di-t-butyl-phenyl phosphonite, (2-methyl-3-pentyl-phenyl) -phenylsulfonate, di- (4-pentyl-phenyl) -phenylphosphonite, di- (3-butyl-4-methyl-phenyl) -phenyl phosphonite, di- (3-hexyl- Ethyl-phenyl) -phenyl phosphonite, di- (2,4,6-trimethylphenyl) -phenyl phosphonite, di- (2,3- - (2,6-diethyl-3-butylphenyl) -phenyl phosphonite, di- (2,3- Tri-t-butylphenyl) -phenyl phosphonite, and diphenyl derivative-phenyl phosphonites.

Examples of the phosphonate compound represented by Chemical Formula 5 include tetrakis (2,4-di-t-butyl-phenyl) -4,4'-biphenylene diphosphonite, tetrakis (3,5-di-t-butyl-phenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3,4-trimethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3-dimethyl-5-ethyl-phenyl) -4,4'-biphenylene diphosphonite Tetrakis (2,3-dimethyl-4-propylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3- Biphenylene diphosphonite, tetrakis (2,5-dimethyl-4-t-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3-diethyl- Tetrakis (2,6-diethyl-4-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4,5-tri Ethyl phenyl) -4,4'-biphenylene diphospho Tetrakis (2,6-diethyl-4-propylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5-diethyl- Biphenylene diphosphonite, tetrakis (2,3-diethyl-5-t-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5- t-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3-dipropyl 5-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis Dipropyl-4-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,6-dipropyl-5-ethylphenyl) -4,4'-biphenylene diphosphonite, tetra (2,3-dipropyl-6-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,6-dipropyl-5-butylphenyl) (2,3-dibutyl-4-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5-dibutyl-3-methylphenyl) '-Biphenylene diphosphonite, tetrakis (2 (2,4-di-t-butyl-3-methylphenyl) -4,4'-biphenylene diphosphate Tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4- (2,5-di-t-butyl-3-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5- Butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5-di-t-butyl-6-methylphenyl) Tetrakis (2,6-di-t-butyl-3-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis -4,4'-biphenylene diphosphonite, tetrakis (2,6-di-t-butyl-5-methylphenyl) -4,4'-biphenylene diphosphonite, tetrakis Dibutyl-4-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4-dibutyl-3-ethylphenyl (2,5-dibutyl-4-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4- Di-t-butyl-3-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4- (2,4-di-t-butyl-6-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5- -Ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5-di-t-butyl-4-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,5-di-t-butyl-6-ethylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,6- 4'-biphenylene diphosphonite, tetrakis (2,6-di-t-butyl-4-ethylphenyl) butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,3,4-tributylphenyl) -4,4'-biphenyl Diphosphonium there may be mentioned nitro, tetrakis (2,4,6--t- butylphenyl) -4,4'-biphenylene diphosphonite, etc.

In the present invention, the phosphonite compound represented by the general formula (5) is preferable. Among them, 4,4'-biphenylene diphosphonite compounds such as tetrakis (2,4-di-t-butyl-phenyl) -4,4'-biphenylene diphosphonite are preferable, Tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene diphosphonite is suitable.

Particularly preferred phosphonite compounds are shown below.

The content of the phosphorus compound is usually 0.001 to 10.0 parts by mass, preferably 0.01 to 5.0 parts by mass, more preferably 0.1 to 1.0 parts by mass based on 100 parts by mass of the cellulose ester.

The carbon radical scavenger, the phenolic compound and the phosphorous compound are preferably used in combination of three kinds, and the more preferable range of the added amount is 0.1 to 1.0 part by mass of the carbon radical scavenger, 100 to 200 parts by mass of the phenolic compound And 0.2 to 2.0 parts by mass of the phosphorus compound and 0.1 to 1.0 parts by mass of the phosphorus compound, respectively. When the addition amount of the three compounds is within the above range, it is clear that the respective compounds have a synergistic effect and the performance improves.

(Cellulose ester)

The cellulose ester according to the present invention is a cellulose ester or a mixed acid ester containing any one of a fatty acid acyl group and a substituted or unsubstituted aromatic acyl group.

In the aromatic acyl group, when the aromatic ring is a benzene ring, examples of the substituent of the benzene ring include a halogen atom, a cyano group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, a carboxylamide group, a sulfonamide group, , An arylalkyl group, an arylalkyl group, an arylalkylcarbonyl group, an arylalkylcarbonyl group, a carbamoyl group, a sulfamoyl group, an acyloxy group, an alkenyl group, an alkynyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkyloxysulfonyl group, -SH, -NH-CO-OR, -PH-R, -P (-R) ₂ , -PH-O-R, -P -R) (- OR), -P (-0-R) 2, -PH (= O) -RP (= 0) (- R) 2, -PH (= O) -OR, -P (= O ) (- R) (- OR ), -P (= O) (- 0-R) 2, -O-PH (= O) -R, -OP (= O) (- R) 2 -O-PH (= O) -OR, -OP ( = 0) (- R) (- OR), -OP (= O) (- OR) 2, -NH-PH (= O) -R, -NH-P ( = O) (- R) ( - OR), -NH-P (= 0) (- OR) 2, -SiH 2 -R, -SiH (-R) 2, -Si (-R) 3, -O -SiH ₂ -R, -O-SiH (-R) ₂ and -O-Si (-R) ₃ . Wherein R is an aliphatic group, an aromatic group or a heterocyclic group. The number of substituents is preferably 1 to 5, more preferably 1 to 4, further preferably 1 to 3, most preferably 1 or 2. As the substituent, a halogen atom, a cyano, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, a carboxylamide group, a sulfonamide group and a ureido group are preferable, and a halogen atom, a cyano, More preferably a halogen atom, a cyano, an alkyl group, an alkoxy group and an aryloxy group, and most preferably a halogen atom, an alkyl group and an alkoxy group.

The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The alkyl group may have a cyclic structure or a branch. The number of carbon atoms of the alkyl group is preferably from 1 to 20, more preferably from 1 to 12, still more preferably from 1 to 6, and most preferably from 1 to 4. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, t-butyl, hexyl, cyclohexyl, octyl and 2-ethylhexyl. The alkoxy group may have a cyclic structure or a branch. The number of carbon atoms of the alkoxy group is preferably from 1 to 20, more preferably from 1 to 12, even more preferably from 1 to 6, and most preferably from 1 to 4. The alkoxy group may be further substituted with another alkoxy group. Examples of alkoxy groups include methoxy, ethoxy, 2-methoxyethoxy, 2-methoxy-2-ethoxyethoxy, butyloxy, hexyloxy and octyloxy.

The number of carbon atoms of the aryl group is preferably from 6 to 20, more preferably from 6 to 12. Examples of aryl groups include phenyl and naphthyl. The number of carbon atoms of the aryloxy group is preferably from 6 to 20, more preferably from 6 to 12. Examples of aryloxy groups include phenoxy and naphthoxy. The number of carbon atoms of the acyl group is preferably from 1 to 20, more preferably from 1 to 12. Examples of acyl groups include formyl, acetyl and benzoyl. The number of carbon atoms of the carboxylamide group is preferably from 1 to 20, more preferably from 1 to 12. Examples of the carboxylamide group include acetamide and benzamide. The number of carbon atoms of the sulfonamide group is preferably from 1 to 20, more preferably from 1 to 12. Examples of sulfonamide groups include methanesulfonamide, benzenesulfonamide and p-toluenesulfonamide. The number of carbon atoms in the ureido group is preferably from 1 to 20, more preferably from 1 to 12. Examples of ureido groups include (unsubstituted) ureido groups.

The number of carbon atoms of the arylalkyl group is preferably from 7 to 20, more preferably from 7 to 12. Examples of arylalkyl groups include benzyl, phenethyl and naphthylmethyl. The number of carbon atoms of the alkoxycarbonyl group is preferably from 1 to 20, more preferably from 2 to 12. Examples of the alkoxycarbonyl group include methoxycarbonyl. The number of carbon atoms of the aryloxycarbonyl group is preferably from 7 to 20, more preferably from 7 to 12. Examples of the aryloxycarbonyl group include phenoxycarbonyl. The number of carbon atoms of the arylalkyloxycarbonyl group is preferably 8 to 20, more preferably 8 to 12. Examples of the arylalkyloxycarbonyl group include benzyloxycarbonyl. The number of carbon atoms of the carbamoyl group is preferably from 1 to 20, more preferably from 1 to 12. Examples of carbamoyl groups include (unsubstituted) carbamoyl and N-methylcarbamoyl. The number of carbon atoms of the sulfamoyl group is preferably 20 or less, more preferably 12 or less. Examples of sulfamoyl groups include (unsubstituted) sulfamoyl and N-methylsulfamoyl. The number of carbon atoms of the acyloxy group is preferably from 1 to 20, more preferably from 2 to 12. Examples of acyloxy groups include acetoxy and benzoyloxy.

The number of carbon atoms of the alkenyl group is preferably from 2 to 20, more preferably from 2 to 12. Examples of alkenyl groups include vinyl, allyl and isopropenyl. The number of carbon atoms of the alkynyl group is preferably from 2 to 20, more preferably from 2 to 12. Examples of the alkynyl group include thienyl. The number of carbon atoms of the alkylsulfonyl group is preferably from 1 to 20, more preferably from 1 to 12. The number of carbon atoms of the arylsulfonyl group is preferably from 6 to 20, more preferably from 6 to 12. The number of carbon atoms of the alkyloxysulfonyl group is preferably from 1 to 20, more preferably from 1 to 12. The number of carbon atoms of the aryloxysulfonyl group is preferably 6 to 20, more preferably 6 to 12. The number of carbon atoms of the alkylsulfonyloxy group is preferably from 1 to 20, more preferably from 1 to 12. The number of carbon atoms of the aryloxysulfonyl group is preferably 6 to 20, more preferably 6 to 12.

In the cellulose ester according to the present invention, when the hydrogen atom of the hydroxyl group portion of the cellulose is a fatty acid ester with an aliphatic acyl group, the aliphatic acyl group has 2 to 20 carbon atoms and specifically includes acetyl, propionyl, butyryl, isobutyryl , Valeryl, pivaloyl, hexanoyl, octanoyl, lauroyl, stearoyl and the like.

In the present invention, the aliphatic acyl group includes those having a further substituent. Examples of the substituent include those exemplified as the substituent of the benzene ring when the aromatic ring is a benzene ring in the above-mentioned aromatic acyl group.

When the esterified substituent of the cellulose ester is an aromatic ring, the number of substituents X substituted with an aromatic ring is 0 or 1 to 5, preferably 1 to 3, and particularly preferably 1 or 2. When two or more substituents are substituted by an aromatic ring, they may be the same or different and they may be linked to each other to form a condensed polycyclic compound (e.g., naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, Chromene, chroman, phthalazine, acridine, indole, indoline, etc.) may be formed.

At least one selected from the group consisting of a substituted or unsubstituted aliphatic acyl group and a substituted or unsubstituted aromatic acyl group in the cellulose ester is used as the structure used in the cellulose ester of the present invention, Mixed acid esters or a mixture of two or more kinds of cellulose esters may be used.

The cellulose ester according to the present invention is selected from cellulose acetate, cellulose propionate, cellulose butyrate, cellulose pentanate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate pentaneate, cellulose acetate phthalate and cellulose phthalate Is preferable.

The glucose units constituting the cellulose by the? -1,4-glycoside bond have hydroxyl groups at the 2nd, 3rd and 6th positions on the glass. The cellulose ester in the present invention is a polymer (polymer) obtained by esterifying a part or all of these hydroxyl groups with an acyl group. The substitution degree represents the sum of the ratios of esterification of cellulose to the second, third and sixth positions of the repeating unit. Concretely, when the hydroxyl groups at the 2nd, 3rd and 6th positions of cellulose are 100% esterified, they are referred to as substitution degree 1, respectively. Therefore, when the second, third, and sixth positions of cellulose are 100% esterified, the degree of substitution becomes maximum 3. The substitution degree of the acyl group can be obtained by the method defined in ASTM-D817.

As a degree of substitution of the mixed fatty acid ester, a more preferable cellulose ester has an acyl group having 2 to 5 carbon atoms as a substituent, a substitution degree of an acetyl group as A, a total degree of substitution of an acyl group having 3 to 5 carbon atoms as B Is a cellulose resin containing a cellulose ester satisfying the following formulas (1) to (3) simultaneously.

<Formula 1>

2.4? A + B? 3.0

<Formula 2>

0? A? 2.4

<Formula 3>

0.1? B <3.0

Of these, cellulose acetate propionate is particularly preferably used, and in particular, 1.00? A? 2.20 and 0.50? B? 2.00 are preferable. More preferably 1.20? A? 2.00, and 0.70? B? 1.70. The part not substituted with the acyl group usually exists as a hydroxyl group. These can be synthesized by a known method.

The cellulose ester used in the present invention preferably has a weight-average molecular weight (Mw) / number-average molecular weight (Mn) ratio of 1.5 to 5.5, particularly preferably 2.0 to 4.0.

The cellulose ester according to the present invention preferably has a number average molecular weight (Mn) of 50,000 to 150,000, more preferably a number average molecular weight of 55,000 to 120,000, and most preferably a number average molecular weight of 60,000 to 100,000 Do.

Mn and Mw / Mn were calculated by gel permeation chromatography in the following manner.

The measurement conditions are as follows.

Solvent: tetrahydrofuran

Apparatus: HLC-8220 (manufactured by Tosoh Corporation)

Column: TSKgel SuperHM-M (manufactured by Tosoh Corporation)

Column temperature: 40 DEG C

Sample concentration: 0.1 mass%

Injection volume: 10 μl

Flow rate: 0.6 ml / min

Calibration curve: A calibration curve of 9 samples with standard polystyrene: PS-1 (from Polymer Laboratories) Mw = 2,560,000 to 580 was used.

The raw cellulose of the cellulose ester used in the present invention may be a wood pulp or a cotton linter, and the wood pulp may be coniferous or hardwood, but coniferous wood is more preferable. A cotton linter is preferably used in terms of peelability at the time of film formation. The cellulose esters produced therefrom may be mixed as appropriate or used alone.

For example, the ratio of cellulose ester derived from cotton linter: cellulose ester derived from wood pulp (softwood) to cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0:15, 40:30:30.

The cellulose ester can be obtained by, for example, replacing the acetyl group, the propionyl group and / or the butyryl group within the above-mentioned range by a conventional method using a carboxylic acid anhydride, acetic anhydride and / or anhydrous butyric acid as a raw material cellulose Can be obtained. The method for synthesizing such a cellulose ester is not particularly limited, but can be synthesized with reference to the methods described in, for example, JP-A 10-45804 or JP 6-501040.

The content of the alkaline earth metal in the cellulose ester used in the present invention is preferably in the range of 1 to 50 ppm. When the amount is more than 50 ppm, the lip adhesion is liable to increase or it tends to break at the thermal expansion or at the slitting part after thermal expansion. It tends to break even at less than 1 ppm, and the reason for this is unknown. To less than 1 ppm, the burden of the cleaning process becomes excessively large, which is also undesirable. And a range of 1 to 30 ppm is preferable. The alkaline earth metal referred to herein is the total content of Ca and Mg, and can be measured using an X-ray photoelectron spectroscopic analyzer (XPS).

The residual sulfuric acid content in the cellulose ester used in the present invention is preferably in the range of 0.1 to 45 ppm in terms of sulfur element. They are believed to be in the form of salts. If the content of residual sulfuric acid exceeds 45 ppm, adherence of the die lip portion at the time of heat melting increases, which is not preferable. Further, it is not preferable since it tends to break at the time of heat elongation or slitting after heat elongation. But it is undesirable because the burden of the washing step of the cellulose ester becomes excessively large in order to be less than 0.1, which is not preferable, and conversely, the cellulose ester may be easily broken. This may be because the increase in the number of rinsing affects the resin, but it is not well known. And a range of 1 to 30 ppm is preferable. The residual sulfuric acid content can be measured according to the method specified in ASTM-D817.

The content of the free acid in the cellulose ester used in the present invention is preferably 1 to 500 ppm. If it exceeds 500 ppm, the adherence of the die lip portion increases, and it tends to break easily. It is difficult to reduce the amount to less than 1 ppm by washing. Further, it is preferably in the range of 1 to 100 ppm, and it is more difficult to break. Particularly preferably in the range of 1 to 70 ppm. The free acid content can be measured according to the method specified in ASTM-D817.

When the cellulose ester synthesized is more thoroughly washed than in the solution casting method, the residual acid content can be kept within the above range. When the film is produced by the melt-blowing method, A film having excellent planarity can be obtained, and a film having good dimensional change, mechanical strength, transparency, moisture resistance, and retardation value described later can be obtained. In addition, in addition to water, a poor solvent such as methanol or ethanol or a poor solvent may be used as the cleaning solvent for the cellulose ester, and a mixed solvent of a poor solvent and a good solvent may be used, and an inorganic or low-molecular organic impurity other than the residual acid may be removed can do. Further, washing of the cellulose ester is preferably carried out in the presence of an antioxidant such as hindered amine, hindered phenol, phosphorus compound (phosphite, phosphonite, etc.), and the heat resistance and film forming stability of the cellulose ester are improved.

Further, since the cellulose ester is improved in heat resistance, mechanical properties, optical properties and the like, it can be dissolved in a good solvent for the cellulose ester and re-precipitated in a poor solvent to remove low molecular weight components and other impurities of the cellulose ester. At this time, it is preferable to carry out in the presence of an antioxidant as in the case of washing the above-mentioned cellulose ester.

After the reprecipitation treatment of the cellulose ester, another polymer or a low-molecular compound may be added.

In the present invention, in addition to the cellulose ester resin, a cellulose ester resin, a vinyl resin (including a polyvinyl acetate resin and a polyvinyl alcohol resin), a cyclic olefin resin, a polyester resin (an aromatic polyester, , Or copolymers thereof), acrylic resins (including copolymers), and the like. The content of the resin other than the cellulose ester is preferably 0.1 to 30 mass%.

In addition, the cellulose ester used in the present invention preferably has few foreign objects in the form of a film. The spot foreign object means a state in which two polarizing plates are arranged orthogonally (Cross Nicol), a cellulose ester optical film is arranged therebetween, the light of the light source is irradiated from one side, and the cellulose ester optical film is observed from the other side , The point where light from the light source leaks out. At this time, the polarizing plate used in the evaluation is preferably composed of a protective film free from foreign matter, and a glass plate is preferably used for protecting the polarizer. The foreign matter of the spots is considered to be one of the causes of the microsylation or low acylation of cellulose contained in the cellulose ester, so that the cellulose ester having less foreign matter is used (cellulose ester having a small degree of substitution degree is used) At least one of the steps of filtering a cellulose ester or the step of synthesizing a cellulose ester or obtaining a precipitate may be carried out once in a solution state and the foreign matters may be removed via a filtration step. Since the molten resin has a high viscosity, the latter method is more efficient.

However, such fine particles may not be entirely taken by filtration. The present inventors have found that a polymer having an amide structure specific to a cellulose ester and a polymer selected from the group consisting of a carbon radical scavenger, a phenol compound and a phosphorus compound , The occurrence of spots of foreign matter can be significantly reduced. The cause is not clear, but it is presumed that the low acylate causing the foreign object was fully melted.

As the thickness of the film becomes thinner, the number of spot foreign objects per unit area decreases. As the content of the cellulose ester contained in the film decreases, the foreign matter tends to decrease as the film thickness decreases. dog / cm ² or less is preferred, but also to 100 / cm ² or less is preferable, and 50 / cm ² or less is preferable, and 30 / cm ² or less is preferred is preferable, and 10 / cm ² or less, It is most desirable to have none. Further, it is preferable from 0.005 to one to about 200 spots of 0.01mm or less / cm ² or less, and further preferably it is preferable, and 50 / cm ² is preferable, and 30 / cm ² or less than 100 / cm ² or less Cm &lt; ² &gt; or less, but most preferably, no more than 10 / cm &lt; ² &gt;.

When foreign matter is removed by melt filtration, it is preferable to filter a composition containing a plasticizer, an anti-deterioration agent, and the like, rather than filtrating the cellulose ester alone by filtration. Of course, it may be dissolved in a solvent at the time of synthesis of the cellulose ester and reduced by filtration. Ultraviolet absorbers, and other additives may be appropriately mixed to be filtered. It is preferable that the filtration is performed at a viscosity of not more than 10,000 Pa · s, more preferably not more than 5000 Pa · s, more preferably not more than 1,000 Pa · s, even more preferably not more than 500 Pa · s, in the melt containing the cellulose ester Do. As the filter material, conventionally known ones such as glass fiber, cellulose fiber, fleece, and fluorine resin such as ethylene tetrafluoride resin are preferably used, and ceramics, metal and the like are particularly preferably used. The absolute filtration accuracy is preferably 50 μm or less, more preferably 30 μm or less, more preferably 10 μm or less, and most preferably 5 μm or less. These may be used in appropriate combinations. The filter material can be used either as a surface type or as a dip-type filter, but is preferably used because a dip-filter can not be blocked relatively well.

In another embodiment, the cellulose ester as the raw material may be dissolved in the solvent at least once, or may be suspended in the solvent, and then the solvent may be dried to use the cellulose ester. At this time, the cellulose ester may be used after dissolving it in a solvent together with at least one of a plasticizer, an ultraviolet absorber, an anti-deterioration agent, an antioxidant and a mat agent, or after suspending and washing in a solvent. As the solvent, a good solvent to be used in the solution casting method such as methylene chloride, methyl acetate or dioxolane may be used, or a poor solvent such as methanol, ethanol or butanol may be used, or a mixed solvent thereof may be used good. It may be cooled to -20 캜 or lower in the dissolution process, or heated to 80 캜 or higher. When such a cellulose ester is used, it is easy to make each additive uniform in the molten state, and the optical characteristics can be made uniform.

(Plasticizer)

The cellulose ester optical film of the present invention preferably contains at least one ester plasticizer comprising a carboxylic acid having a monovalent polyvalent alcohol as a plasticizer. In particular, the cellulose ester optical film preferably contains an organic acid represented by the following general formula (7) It is preferable that the ester compound having a condensed structure is contained in an amount of 1 to 25 mass% as a plasticizer. If it is less than 1% by mass, the effect of adding a plasticizer is not recognized, and if it is more than 25% by mass, bleeding-out is liable to occur and stability of the film with time is lowered. More preferably, it is a cellulose ester optical film containing 3 to 20 mass% of the above plasticizer, more preferably 5 to 15 mass% of a cellulose ester optical film.

The plasticizer generally has an effect of improving the fragility or imparting flexibility by adding it to the polymer. In the present invention, in order to lower the melting temperature in the cellulose ester alone and at the same heating temperature A plasticizer is added in order to lower the melt viscosity of the film composition containing the plasticizer rather than the cellulose resin alone. Further, it is also added to improve the hydrophilicity of the cellulose ester and to improve the moisture permeability of the optical film, and thus has a function as a moisture permeation preventive agent.

Here, the melting temperature of the film composition means a temperature at which the material is heated to exhibit fluidity. In order to melt-flow the cellulose ester, it is necessary to heat it at least to a temperature higher than the glass transition temperature. Above the glass transition temperature, the elastic modulus or viscosity decreases due to the absorption of the heat, and the fluidity is expressed. However, in a cellulose ester, it is necessary to melt the cellulose ester at a temperature as low as possible since the molecular weight of the cellulose ester is lowered due to thermal decomposition at the same time as melting at a high temperature, and adversely affecting the mechanical properties of the resulting film. The lowering of the melting temperature of the film composition can be achieved by adding a plasticizer having a melting point or glass transition temperature lower than the glass transition temperature of the cellulose ester. The polyhydric alcohol ester plasticizer having a structure in which an organic acid represented by the following formula (7) is condensed with a polyhydric alcohol, used in the present invention, lowers the melting temperature of the cellulose ester and is low in volatility after the melt- And the cellulose ester film obtained is excellent in that optical properties, dimensional stability and planarity of the obtained cellulose ester film are improved.

&Lt; Formula 7 >

In formula (7), R ⁵¹ to R ^{55 each} represent a hydrogen atom or a cycloalkyl group, an arylalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an arylalkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, And L may represent a divalent linking group and represents a substituted or unsubstituted alkylene group, an oxygen atom or a direct bond.

As the cycloalkyl group represented by R ⁵¹ to R ⁵⁵ , a cycloalkyl group having 3 to 8 carbon atoms is preferable, and specific examples thereof include cyclopropyl, cyclopentyl, cyclohexyl, and the like. These groups may be substituted. Preferable examples of the substituent include a halogen atom such as a chlorine atom, a bromine atom and a fluorine atom, a hydroxyl group, an alkyl group, an alkoxy group, a cycloalkoxy group and an arylalkyl group An alkenyl group such as a vinyl group or an allyl group, a phenyl group (which may further be substituted by an alkyl group or a halogen atom), a phenoxy group (the phenyl group may be substituted with an alkyl group or a halogen atom, An acyl group having 2 to 8 carbon atoms such as an acetyl group and a propionyl group and an unsubstituted carbonyloxy group having 2 to 8 carbon atoms such as an acetyloxy group and a propionyloxy group, .

The arylalkyl group represented by R ⁵¹ to R ⁵⁵ represents a group such as a benzyl group, a phenethyl group, a γ-phenylpropyl group, etc. These groups may be substituted, and preferable examples of the substituent include the above- A good flag can be heard as well.

Examples of the alkoxy group represented by R ⁵¹ to R ⁵⁵ include an alkoxy group having 1 to 8 carbon atoms. Specific examples thereof include methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, Butyl, isobutoxy, 2-ethylhexyloxy, or t-butoxy. These groups may be substituted. Preferable examples of the substituent include halogen atoms such as a chlorine atom, a bromine atom and a fluorine atom, a hydroxyl group, an alkoxy group, a cycloalkoxy group and an arylalkyl group (Wherein the phenyl group may further be substituted with an alkyl group or a halogen atom), an aryloxy group (e.g., a phenoxy group, which is further substituted by an alkyl group or a halogen atom, etc. in the phenyl group), an alkenyl group An acyl group such as an acetyl group or a propionyl group, an unsubstituted acyloxy group having a carbon number of 2 to 8 such as an acetyloxy group or a propionyloxy group, or an arylcarbonyl group such as a benzoyloxy group And an oxy group.

In the cycloalkoxy group represented by R ⁵¹ to R ⁵⁵ , examples of the unsubstituted cycloalkoxy group include a cycloalkoxy group having 1 to 8 carbon atoms, and specific examples thereof include cyclopropyloxy, cyclopentyloxy, cyclohexyloxy and the like groups . These groups may be substituted. Preferred examples of the substituent include groups which may be substituted with the above-mentioned cycloalkyl group.

The aryloxy group represented by R ⁵¹ to R ⁵⁵ includes a phenoxy group. The phenyl group may be substituted with a substituent such as an alkyl group or a halogen atom, which may be substituted with the above-mentioned cycloalkyl group.

Examples of the arylalkyloxy group represented by R ⁵¹ to R ⁵⁵ include a benzyloxy group and a phenethyloxy group. These substituents may be further substituted. Preferred examples of the substituent include those substituted with the above-mentioned cycloalkyl group A good flag can be heard as well.

Examples of the acyl group represented by R ⁵¹ to R ⁵⁵ include an unsubstituted acyl group having 2 to 8 carbon atoms such as an acetyl group and a propionyl group (the hydrocarbon group of the acyl group includes alkyl, alkenyl, and alkynyl groups These substituents may be further substituted. Preferable examples of the substituent include groups which may be substituted with the above-mentioned cycloalkyl group.

Examples of the carbonyloxy group represented by R ⁵¹ to R ⁵⁵ include an unsubstituted acyloxy group having 2 to 8 carbon atoms such as an acetyloxy group and a propionyloxy group (examples of the hydrocarbon group of the acyl group include alkyl, alkenyl, alkynyl And an arylcarbonyloxy group such as a benzoyloxy group. These groups may be substituted by the same group as the group which may be substituted with the above-mentioned cycloalkyl group.

The oxycarbonyl group represented by R ⁵¹ to R ⁵⁵ represents an alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group or a propyloxycarbonyl group, or an aryloxycarbonyl group such as a phenoxycarbonyl group. These substituents may be further substituted, and preferable examples of the substituent include groups which may be substituted with the above-mentioned cycloalkyl group.

The oxycarbonyloxy group represented by R ⁵¹ to R ⁵⁵ represents an alkoxycarbonyloxy group having 1 to 8 carbon atoms such as a methoxycarbonyloxy group. These substituents may be further substituted, and preferred substituents are , And a group which may be substituted with the above-mentioned cycloalkyl group.

Either R ⁵¹ to R ⁵⁵ may be connected to each other to form a ring structure.

The linking group represented by L represents a substituted or unsubstituted alkylene group, an oxygen atom or a direct bond. Examples of the alkylene group include a methylene group, an ethylene group and a propylene group, ^May be substituted with a group which may be substituted with a group represented by R ⁵¹ to R ⁵⁵ .

Among them, particularly preferred as a linking group represented by L is a direct bond and an aromatic carboxylic acid.

In the present invention, the organic acid which substitutes the hydroxyl group of the trivalent or higher alcohol may be a single species or a plurality of species.

In the present invention, the tri- or higher-valent alcohol compound which reacts with the organic acid represented by the above-mentioned formula (7) to form a polyhydric alcohol ester compound is preferably an aliphatic polyhydric alcohol having 3 to 20 carbon atoms. In the present invention, Is preferably represented by the following formula (8).

(8)

R '- (OH) m

In the formula, R 'is an organic group of m, m is a positive integer of 3 or more, and the OH group represents an alcoholic hydroxyl group. Especially preferred is m is 3 or 4 polyhydric alcohols.

Examples of preferred polyhydric alcohols include, but are not limited to, the following. There may be mentioned adonitol, arabitol, 1,2,4-butanetriol, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glycerin, diglycerin, erythritol, pentaerythritol, di Pentaerythritol, tripentaerythritol, galactitol, glucose, cellobiose, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol . Particularly, glycerin, trimethylolethane, trimethylol propane and pentaerythritol are preferable.

The ester of the organic acid represented by the general formula (7) and the polyhydric alcohol having three or more valences can be synthesized by a known method. A method of condensing an organic acid represented by the general formula (7) with a polyhydric alcohol in the presence of an acid to effect esterification, a method in which an organic acid is previously made into an acid chloride or an acid anhydride and reacted with a polyhydric alcohol, A method of reacting a phenyl ester with a polyhydric alcohol, and the like, and it is preferable to select a method that yields an appropriate yield by using an objective ester compound.

As the plasticizer comprising an ester of an organic acid represented by the general formula (7) and a polyvalent alcohol having three or more valences, a compound represented by the following general formula (9) is preferable.

&Lt; Formula 9 >

In formula (9), R ⁶¹ to R ^{65 each} represent a hydrogen atom or a group selected from the group consisting of a cycloalkyl group, an arylalkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an arylalkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, Or an oxy group, and these may further have a substituent. Also, R ⁶⁶ represents an alkyl group.

R ⁶¹ to a cycloalkyl group, an aryl group of R ^65, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aryl oxy group, an acyl group, a carbonyl oxy group, oxycarbonyl group, butyloxycarbonyl for groups alkyloxy, said R ⁵¹ to R &lt; ⁵⁵ &gt;

The molecular weight of the polyhydric alcohol ester thus obtained is not particularly limited, but is preferably 300 to 1500, more preferably 400 to 1000. A larger molecular weight is preferred because it is less likely to be volatilized. A smaller molecular weight is desirable in view of its moisture permeability and compatibility with cellulose esters.

Specific compounds of polyhydric alcohol esters according to the present invention are exemplified below.

delete

The cellulose ester optical film of the present invention may be used in combination with another plasticizer.

The ester compound comprising the organic acid represented by the general formula (7) and the polyhydric alcohol having three or more valences, which is a preferred plasticizer in the present invention, is highly compatible with the cellulose ester and can be added at a high addition rate. , Bleeding-out does not occur, and plasticizers and additives of other species can be easily used in combination if necessary.

When another plasticizer is used in combination, it is preferable that an ester compound comprising the organic acid represented by the above formula (7) and a polyvalent alcohol having three or more valences is contained in an amount of at least 50 mass% or more of the entire plasticizer. , More preferably not less than 70%, and even more preferably not less than 80%. When used in such a range, it is possible to obtain a certain effect that can improve the planarity of the cellulose ester film at the time of melt bending even when used in combination with another plasticizer.

Other preferred plasticizers include the following plasticizers.

Examples of the ethylene glycol ester-based plasticizer which is one of polyhydric alcohol ester-based ones: specifically, an ethylene glycol alkyl ester-based plasticizer such as ethylene glycol diacetate and ethylene glycol dibutyrate; a plasticizer such as ethylene glycol dicyclopropyl carboxylate, Ethylene glycol cycloalkyl ester-based plasticizers such as hexyl carboxylate, and ethylene glycol aryl ester-based plasticizers such as ethylene glycol dibenzoate and ethylene glycol di-4-methoxybenzoate. These alkylating groups, cycloalkylating groups and arylating groups may be the same or different and may be substituted. In addition, a mixture of an alkylating group, a cycloalkylating group and an arylating group may be used, or these substituents may be bonded to each other through a covalent bond. The ethylene glycol moiety may also be substituted, and the partial structure of the ethylene glycol ester may be partly or regularly pendant of the polymer, and may be introduced into a part of the molecular structure of an additive such as an antioxidant, an acid scavenger or an ultraviolet absorber .

Glycerin ester-based plasticizers such as triacetin, tributylin, glycerin diacetate caprylate, and glycerol oleate propionate; glycerin alkyl esters such as glycerin tricyclopropyl carboxylate, Glycerin cycloalkyl alkyl esters such as glycerin tricyclohexyl carboxylate, diglycerin tetraacetylate, diglycerin tetra propionate, diglycerin acetate tricaprylate, diglycerin tetra laurate and the like, diglycerin tetra And diglycerin cycloalkyl esters such as cyclobutyl carboxylate and diglycerin tetracyclopentyl carboxylate. These alkylating groups and cycloalkylcarboxylate groups may be the same or different and may be substituted. In addition, a mixture of an alkylate group, a cycloalkylcarboxylate group and an arylate group may be used, or these substituents may be bonded to each other through a covalent bond. In addition, glycerin and diglycerin moieties may be substituted, and the partial structure of the glycerin ester and the diglycerol ester may be partly or regularly pendant of the polymer, and the molecular structure of additives such as an antioxidant, an acid scavenger, and an ultraviolet absorber As shown in FIG.

Other examples of the polyhydric alcohol ester-based plasticizer include the polyhydric alcohol ester-based plasticizers described in paragraphs 30 to 33 of JP-A-2003-12823.

Specific examples of the dicarboxylic acid ester-based plasticizer which is one kind of polyvalent carboxylic acid ester include: alkyl dicarboxylic acids such as didodecyl malonate (C1), dioctyl adipate (C4) and dibutyl sebacate (C8) Alkyl dicarboxylic acid cycloalkyl ester plasticizers such as dicyclohexyl adipate and dicyclohexyl adipate, alkyldicarboxylic acids such as diphenyl succinate and di-4-methylphenyl glutarate, A cycloalkyl dicarboxylic acid alkyl ester such as a dicyclohexyl dicarboxylate, a dicyclohexyl dicarboxylate, and a diglycidyl cyclo [2.2.1] heptane-2,3-dicarboxylate; Cyclic dicarboxylic acid cycloalkyl ester-based plasticizers such as dicyclohexyl-1,2-cyclobutane dicarboxylate and dicyclopropyl-1,2-cyclohexyl dicarboxylate, diphenyl -1,1- Cycloalkyldicarboxylic acid aryl ester-based plasticizers such as di-naphthyl-1,4-cyclohexanedicarboxylate and di-naphthyl-1,4-cyclohexanedicarboxylate, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl Aryl dicarboxylic acid alkyl ester-based plasticizers such as phthalate and di-2-ethylhexyl phthalate, plasticizers of aryl dicarboxylic acid cycloalkyl ester such as dicyclopropyl phthalate and dicyclohexyl phthalate, And aryl dicarboxylic acid aryl ester-based plasticizers such as 4-methylphenyl phthalate. These alkoxy groups and cycloalkoxy groups may be the same or different and may be monosubstituted or may be further substituted with these substituents. The alkyl group and the cycloalkyl group may be mixed or the substituents may be bonded to each other through a covalent bond. Further, the aromatic ring of the phthalic acid may be substituted or a large amount such as a dimer, a trimer or a tetramer may be used. The partial structure of the phthalate ester may be part of the polymer or regularly pendent to the polymer, or may be introduced into a part of the molecular structure of an additive such as an antioxidant, an acid scavenger or an ultraviolet absorber.

Examples of other polyvalent carboxylic acid ester plasticizers include alkyldicarboxylic acid alkyls such as tridodecyl tricarbatate and tributyl-meso-butane-1,2,3,4-tetracarboxylate Ester plasticizers, alkylpolycarboxylic acid cycloalkyl ester plasticizers such as tricyclohexyl tricarbate and tricyclopropyl-2-hydroxy-1,2,3-propane tricarboxylate, triphenyl 2- Hydroxy-1,2,3-propane tricarboxylate, tetra-3-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate, and other alkylpolycarboxylic acid aryl ester-based plasticizers, tetrahexyl Cycloalkylpolycarboxylic acid alkyl ester-based plasticizers such as tetrabutyl-1,2,3,4-cyclobutane tetracarboxylate and tetrabutyl-1,2,3,4-cyclopentanetetracarboxylate, -1,2,3,4-cyclobutanetetracar Cycloalkylpolycarboxylic acid cycloalkyl ester-based plasticizers such as tricyclohexyl-1,3,5-cyclohexyltricarboxylate, triphenyl-1,3,5-cyclohexyltricarboxylate, Cyclohexyldicarboxylic acid aryl ester-based plasticizers such as hexa-4-methylphenyl-1,2,3,4,5,6-cyclohexylhexacarboxylate, trioctylbenzene-1,2,4-tricaryl Tetraoctylbenzene-1,2,4,5-tetracarboxylate, and the like, a plasticizer such as tricyclopentylbenzene-1,3,5-tricarboxylate, tetracyclo Hexylbenzene-1,2,3,5-tetracarboxylate, and other plasticizers such as triphenylbenzene-1,3,5-tetracarboxylate, hexa-4-methylphenylbenzene -1,2,3,4,5,6-hexacarboxylate, and the like. It may be the problem. These alkoxy groups and cycloalkoxy groups may be the same or different and may be monosubstituted or may be further substituted. The alkyl group and the cycloalkyl group may be mixed or the substituents may be bonded by a covalent bond. Further, the aromatic ring of the phthalic acid may be substituted or a large amount such as a dimer, a trimer or a tetramer may be used. The partial structure of the phthalate ester may be partly or regularly pendant to the polymer, or may be introduced into a part of the molecular structure of an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber.

Among the ester-based plasticizers in which the polyvalent carboxylic acid is monovalent alcohol, dialkylcarboxylic acid alkyl esters are preferable, and specific examples thereof include dioctyl adipate and tridecyl tricarbate.

Examples of the plasticizer used in the present invention include a phosphate ester plasticizer, a carbohydrate ester plasticizer, a polymer plasticizer and the like.

Phosphoric acid ester-based plasticizers: specifically, phosphoric acid alkyl esters such as triacetyl phosphate and tributyl phosphate, tricyclobutyl phosphate, cycloalkyl phosphate such as cyclohexyl phosphate, triphenyl phosphate, tricresyl phosphate, cresylphenyl Phosphoric acid aryl esters such as phosphate, octyldiphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, triclosyl phosphate and tris ortho-biphenyl phosphate. These substituents may be the same or different and may be substituted. Further, a mixture of an alkyl group, a cycloalkyl group and an aryl group may be used, or the substituents may be bonded to each other through a covalent bond.

Examples of the alkylene bis (dialkylphosphate) such as ethylenebis (dimethylphosphate) and butylenebis (diethylphosphate), alkylenebis such as ethylenebis (diphenylphosphate) and propylenebis (dinaphthylphosphate) (Dialkylphosphate) such as phenylenebis (diarylphosphate), phenylenebis (dibutylphosphate) and biphenylenebis (dioctylphosphate), phenylenebis (diphenylphosphate), naphthylenebis ) And arylene bis (diaryl phosphates) such as di (meth) acrylate. These substituents may be the same or different and may be substituted. Further, a mixture of an alkyl group, a cycloalkyl group and an aryl group may be used, or the substituents may be bonded to each other through a covalent bond.

The partial structure of the phosphoric acid ester may be partly or regularly pendant of the polymer and may be introduced into a part of the molecular structure of an additive such as an antioxidant, an acid scavenger or an ultraviolet absorber. Among these compounds, aryl phosphate esters and arylene bis (diaryl phosphate) are preferable, and triphenyl phosphate and phenylene bis (diphenyl phosphate) are particularly preferable.

Carbohydrate ester plasticizers: Carbohydrates means monosaccharides, disaccharides or trisaccharides in which the saccharides are in the form of pyranose or furanose (6-membered ring or 5-membered ring). Non-limiting examples of carbohydrates include glucose, saccharose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, cellotriose and raffinose. The carbohydrate ester means that a hydroxyl group and a carboxylic acid of a carbohydrate are dehydrated and condensed to form an ester compound. Specifically, it means an aliphatic carboxylic acid ester of a carbohydrate or an aromatic carboxylic acid ester. Examples of the aliphatic carboxylic acid include, for example, acetic acid and propionic acid. Examples of the aromatic carboxylic acid include benzoic acid, toluic acid, and anisic acid. The carbohydrate has a number of hydroxyl groups depending on the kind thereof. A part of the hydroxyl group may react with the carboxylic acid to form an ester compound, or the whole of the hydroxyl group may react with the carboxylic acid to form an ester compound. In the present invention, it is preferable that all of the hydroxyl groups react with the carboxylic acid to form an ester compound.

Specific examples of the carbohydrate ester-based plasticizer include glucose pentaacetate, glucose penta propionate, glucose penta butyrate, saccharose octaacetate, and saccharose octabenzoate, among which saccharose octabenzoate is more preferable Do.

Specific examples of the polymer plasticizer include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, ethyl polyacrylate, polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate (for example, , And a copolymerization ratio of 1:99 to 99: 1), vinyl polymers such as polyvinyl isobutyl ether and poly N-vinylpyrrolidone, methyl methacrylate and N-vinylpyridine Styrene polymers such as polystyrene and poly-4-hydroxystyrene, copolymers of methyl methacrylate and 4-hydroxy (meth) acrylate, Styrene copolymer (for example, an arbitrary ratio between 1:99 and 99: 1 of copolymerization ratio), polybutylene succinate, polyethylene terephthalate, polyester such as polyethylene naphthalate, polyethylene oxide, polypropyleneThere may be mentioned polyether, polyamide, polyurethane, polyurea, etc. of the seed or the like. The number average molecular weight is preferably about 1,000 to 500,000, particularly preferably about 5000 to 200,000. When the molecular weight is 1000 or less, the volatility becomes large. When the molecular weight exceeds 500,000, the plasticizing ability tends to be lowered, which may adversely affect the mechanical properties of the cellulose ester optical film. These polymer plasticizers may be homopolymers composed of repeating units of one kind of monomers or copolymers having repeating structures of plural kinds of monomers. These polymers may be used in combination of two or more.

In addition, the cellulose ester optical film of the present invention preferably has a yellowness index (yellow index, YI) of 3.0 or less, more preferably 1.0 or less, because coloration affects optical use. Yellowness can be measured based on JIS-K7103.

The plasticizer, like the above-mentioned cellulose ester, preferably removes impurities such as residual acids, inorganic salts, and organic low-molecular substances generated during manufacturing or generated during storage, more preferably 99% or more in purity. The residual acid and water are preferably 0.01 to 100 ppm, and thermal degradation can be suppressed when the cellulose resin is melt-formed, and film-forming stability, optical properties and mechanical properties of the film are improved.

(Ultraviolet absorber)

In the optical film of the present invention, an ultraviolet absorber may be added to prevent the deterioration of the polarizer or the display device against ultraviolet rays. As the ultraviolet absorber, ultraviolet light having a wavelength of 370 nm or less And from the viewpoint of liquid crystal display property, absorption of visible light having a wavelength of 400 nm or more is preferable.

For example, a salicylic acid-based ultraviolet absorber (phenylsalicylate, p-tert-butylsalicylate, etc.) or a benzophenone-based ultraviolet absorber (2,4-dihydroxybenzophenone, 2,2'-dihydroxy- 4,4'-dimethoxybenzophenone, etc.), a benzotriazole-based ultraviolet absorber (2- (2'-hydroxy-3'-tert- butyl-5'-methylphenyl) -5- chlorobenzotriazole, 2- -Hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'- Sol, 2- (2'-hydroxy-3'-dodecyl-5'-methylphenyl) benzotriazole, 2- (2'- Carbonylethyl) -phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ' (2-hydroxy-3 ', 5'-di (1-methyl-1-phenylethyl) -phenyl) benzotriazole and the like), cyanoacrylate Based ultraviolet absorber (2'-ethylhexyl-2-cyano-3,3-diphenylacryl (3 ', 4'-methylene dioxyphenyl) -acrylate), triazine-based ultraviolet absorbers, or Japanese Patent Application Laid-open No. 58-185677, Japanese Patent Laid- 149350, nickel complex salt compounds, inorganic powders and the like.

The ultraviolet absorber according to the present invention is preferably a benzotriazole-based ultraviolet absorber or triazine-based ultraviolet absorber having a high transparency and an excellent effect of preventing the deterioration of the polarizing plate or the liquid crystal element, and a benzotriazole- Is particularly preferable.

The conventionally known benzotriazole-based ultraviolet absorber which is particularly preferably used together with the ultraviolet absorber according to the present invention may be a bis-modified benzotriazole ultraviolet absorber, for example, 6,6'-methylenebis (2- (2H-benzo [d Yl]) - 4- (2,4,4-trimethylpentan-2-yl) phenol, 6,6'- methylenebis (2- (2H- benzo [ d] [1,2,3] triazol-2-yl)) - 4- (2-hydroxyethyl) phenol.

In the present invention, it may be used in combination with conventionally known ultraviolet absorbent polymers. Examples of conventionally known ultraviolet absorbent polymers include, but are not limited to, polymers obtained by homopolymerizing RUVA-93 (manufactured by Otsuka Chemical) and polymers obtained by copolymerizing RUVA-93 and other monomers. Specifically, PUVA-30M, which is a copolymer of RUVA-93 and methyl methacrylate in a ratio of 3: 7 (by mass ratio), and PUVA-50M, which is copolymerized in a ratio of 5: 5 by mass. Polymers described in JP-A-2003-113317 can also be used.

As commercial products, TINUVIN 109, TINUVIN 171, TINUVIN 360, TINUVIN 900, TINUVIN 928 (all manufactured by Shiba Specialty Chemicals), LA-31 (manufactured by Asahi Kasei Corporation), RUVA-100 250 (manufactured by Sumitomo Chemical Co., Ltd.) may be used.

Specific examples of the benzophenone-based compound include 2, 4-dihydroxybenzophenone, 2, 2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy- , Bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane), and the like, but are not limited thereto.

In the present invention, the ultraviolet absorber is preferably added in an amount of 0.1 to 20 mass%, more preferably 0.5 to 10 mass%, further preferably 1 to 5 mass%. These may be used in combination of two or more.

(Fine particles)

In the cellulose ester optical film of the present invention, fine particles such as a matting agent may be added to impart slipperiness. Examples of the fine particles include fine particles of an inorganic compound or fine particles of an organic compound. The matting agent is preferably a fine particle as far as possible. Examples of the fine particle include fine particles such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, Magnesium and calcium phosphate, and crosslinked polymer fine particles. Among them, silicon dioxide is preferable because the haze of the film can be lowered. Fine particles such as silicon dioxide are often surface-treated with an organic material, which is preferable because it can lower the haze of the film.

Preferred examples of the organic material for the surface treatment include halosilanes, alkoxysilanes, silazane, and siloxane. When the average particle diameter of the fine particles is large, the slippery effect is large. On the contrary, when the average particle diameter is small, the transparency is excellent. The average particle size of the fine particles is preferably in the range of 0.005 to 1.0 mu m. These may be primary particles or secondary particles. Particularly preferable average particle size of the fine particles is 5 to 50 nm, more preferably 7 to 14 nm. The average particle diameter can be determined by, for example, observing with a scanning electron microscope and measuring the long diameter of 200 particles randomly. Among these cellulose ester optical films, these fine particles are preferably used because they produce unevenness of 0.01 to 1.0 탆 on the surface of the cellulose ester optical film. The content of the fine particles in the cellulose ester is preferably 0.005 to 5 mass% with respect to the cellulose ester.

Examples of the fine particles of silicon dioxide include AEROSIL 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, NAX50 manufactured by Nippon Aerosil Co., Ltd., SEAHOSTARKE- P100 and SEAHOSTARKE-P30, and preferably Aerosil 200V, R972, R972V, R974, R202, R812, NAX50, KE-P100 and KE-P30. These fine particles may be used in combination of two or more. When two or more of them are used in combination, they can be used in an arbitrary ratio. In this case, fine particles having different average particle diameters and materials such as Aerosil 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9: 0.1.

The presence of fine particles in the film used as the matting agent may be used for the purpose of improving the strength of the film for other purposes. In addition, the presence of the fine particles in the film can improve the orientation of the cellulose ester itself constituting the cellulose ester optical film of the present invention.

(Other additives)

The cellulose ester optical film of the present invention may contain a viscosity reducing agent, a retardation control agent, an acid scavenger, a dye, a pigment and the like in addition to the above plasticizer, UV absorber and fine particles as additives.

(Viscosity reducing agent)

In the present invention, as a purpose of reducing the melt viscosity, a hydrogen-bonding solvent may be added. Hydrogen-binding solvent refers to an electrically negatively charged atom (oxygen, nitrogen, sulfur, nitrogen, and the like) as described in JN Israel Archibilis, "Intermolecular force and surface force" (Condottamos, translated by Oshima Hiroyuki, An organic solvent capable of generating a hydrogen atom-mediated &quot; bond &quot;, that is, an organic solvent having a large bonding moment and occurring in a hydrogen-containing bond, such as hydrogen, fluorine, chlorine, Refers to an organic solvent capable of arranging adjacent molecules by including OH (oxygen-hydrogen bond), NH (hydrogen-nitrogen bond), and FH (fluorine hydrogen bond). This has the ability to form a strong hydrogen bond with cellulose rather than the intermolecular hydrogen bond of the cellulose resin. In the fusion softening method performed in the present invention, the glass transition temperature of the cellulose resin used alone is lower than that of the hydrogen- The melting temperature of the cellulose resin composition can be lowered or the melt viscosity of the cellulose resin composition containing the hydrogen-bonding solvent can be lower than that of the cellulose resin at the same melting temperature.

Examples of the hydrogen-bonding solvent include alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, t-butanol, 2-ethylhexanol, heptanol, Ketones such as acetone, methyl ethyl ketone, methyl ethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, Methyl ethyl ketone and the like; carboxylic acids such as formic acid, acetic acid, propionic acid and butyric acid; ethers such as diethyl ether, tetrahydrofuran and dioxane; pyrrolidones such as N-methyl Pyrrolidone and the like, and amines such as trimethylamine, pyridine and the like. These hydrogen-bonding solvents may be used alone or in combination of two or more. Of these, alcohols, ketones and ethers are preferable, and methanol, ethanol, propanol, isopropanol, octanol, dodecanol, ethylene glycol, glycerin, acetone and tetrahydrofuran are particularly preferable. Further, water-soluble solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerin, acetone and tetrahydrofuran are particularly preferable. Here, the water solubility means that the solubility in 100 g of water is 10 g or more.

(Retardation control agent)

In the cellulose ester optical film of the present invention, a polarizing plate processing may be carried out by forming an alignment film to provide a liquid crystal layer and combining the cellulose ester film with retardation derived from the liquid crystal layer to give an optical compensation ability. As a compound to be added for controlling the retardation, an aromatic compound having two or more aromatic rings such as those described in the specification of European Patent No. 911,656A2 may be used as a retardation control agent. Two or more kinds of aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes, in addition to the aromatic hydrocarbon ring, an aromatic heterocycle. It is particularly preferred that the aromatic heterocycle is an aromatic heterocycle, and the aromatic heterocycle is generally an unsaturated heterocycle. Among them, a compound having a 1,3,5-triazine ring is particularly preferable.

(Acid scavenger)

An acid scavenger is an agent that plays a role of trapping an acid (protonic acid) remaining in a cellulose ester which is passed from the time of production. Further, when the cellulose ester is melted, hydrolysis of the side chain is accelerated by moisture and heat in the polymer, and if cellulose acetate propionate is produced, acetic acid or propionic acid is produced. A compound having an epoxy, a tertiary amine, an ether structure or the like may be used as long as it can be chemically bonded to an acid, but the present invention is not limited thereto.

Specifically, it is preferable to include an epoxy compound as an acid scavenger described in U.S. Patent No. 4,137,201. The epoxy compounds as such acid scavengers are known in the art and include diglycidyl ethers of various polyglycols, especially polyglycols derived from condensation of about 8 to 40 moles of ethylene oxide per mole of polyglycol , Diglycidyl ether of glycerol, metal epoxy compounds (such as those conventionally used in vinyl chloride polymer compositions and vinyl chloride polymer compositions), epoxidized ether condensation products, diisocyanates of bisphenol A Glycidyl ethers (i.e., 4,4'-dihydroxy diphenyldimethyl methane), epoxidized unsaturated fatty acid esters (in particular, alkyl esters of about 4 to about 2 carbon atoms of fatty acids of 2 to 22 carbon atoms Butyl epoxystearate)) and various epoxidized long chain fatty acid triglycerides (e.g., a composition such as an epoxidized soybean oil) Epoxidized vegetable oils and other unsaturated natural oils, sometimes referred to as epoxidized natural glycerides or unsaturated fatty acids, whose fatty acids generally contain 12 to 22 carbon atoms do. Particularly preferred are epoxidized resin epoxy compound EPON815c which is a commercially available epoxy group and other epoxidized ether oligomer condensation product of the following formula (10).

In the above formula, n is equal to 0 to 12. Additional possible acid scavengers that may be used include those described in paragraphs 87 to 105 of Japanese Patent Application Laid-Open No. 5-194788.

The acid scavenger, like the above-mentioned cellulose resin, desirably removes impurities such as residual acid, inorganic salt, organic low molecular weight, etc., which are generated during manufacturing or generated during storage, more preferably 99% or more. The residual acid and water are preferably 0.01 to 100 ppm, and when the cellulose resin is melt-formed, thermal deterioration can be suppressed, and film-forming stability, optical properties and mechanical properties of the film are improved.

The acid scavenger may also be referred to as an acid scavenger, an acid scavenger, or an acid catcher. In the present invention, the acid scavenger can be used without any difference depending on these designations.

(Melting and softening method)

The film constituting material is required to have little or no volatile components in the melting and film forming process. This is for the purpose of reducing or avoiding defects in the inside of the film or deterioration of planarity of the film surface by foaming at the time of heating and melting.

The content of the volatile component when the film constituting material is melted is required to be 5 mass% or less, preferably 1.0 mass% or less, more preferably 0.5 mass% or less, and further preferably 0.2 mass% or less. In the present invention, a heating loss from 30 deg. C to 250 deg. C is obtained by using a differential thermal mass measurement apparatus (TG / DTA200 manufactured by Seiko Electronics Co., Ltd.), and the amount of heating loss is determined as the content of the volatile component.

It is preferable that the film constituting material to be used is removed before or at the time of film formation, such as moisture or volatile components represented by the solvent. The so-called known drying method can be applied, and it can be carried out by a method such as a heating method, a depressurization method, a heat decompression method or the like, and it may be carried out under an atmosphere selected from air or nitrogen as an inert gas. When these known drying methods are carried out, it is preferable for the quality of the film to be carried out in a temperature range where the film constituting material is not decomposed.

By drying the film before film formation, the generation of volatile components can be reduced, and the film can be divided and dried in the resin alone or in a mixture of resin and film constituting material with at least one kind of mixture other than resin, or with commercial water. The drying temperature is preferably 100 DEG C or higher. When the material to be dried has a glass transition temperature, it is preferable that the drying temperature is not higher than the glass transition temperature because heating may cause the material to melt and become difficult to handle when heated to a drying temperature higher than the glass transition temperature. When a plurality of materials have a glass transition temperature, the glass transition temperature of the glass transition temperature is referred to as the lower glass transition temperature. More preferably 100 占 폚 or higher, (glass transition temperature -5 占 폚 or lower, more preferably 110 占 폚 or higher, and (glass transition temperature -20 占 폚 or lower). The drying time is preferably 0.5 to 24 hours, more preferably 1 to 18 hours, further preferably 1.5 to 12 hours. If the drying temperature is too low, the removal rate of the volatile components becomes low, and it takes too much time to dry. The drying step may be divided into two or more steps. For example, the drying step may include a preliminary drying step for storing the material and a preliminary drying step performed between the immediately before the film formation and one week before .

The melt soft-film-forming method is classified into a molding method in which heating and melting are performed, and a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method and the like can be applied. Among them, the melt extrusion method is excellent in order to obtain an optical film excellent in mechanical strength and surface precision. Hereinafter, the production method of the film of the present invention will be described by taking the melt extrusion method as an example.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic flow sheet showing an overall configuration of an apparatus for carrying out a method for producing a cellulose ester optical film of the present invention, and FIG. 2 is an enlarged view of a cooling roll portion from a flexible die.

1 and 2, a method for producing a cellulose ester optical film according to the present invention is a method in which a film material such as a cellulose resin is mixed and then extruded from a flexible die 4 to a first cooling roll 5, and then circumscribed to the first cooling roll 5 and circumscribed in succession to a total of three cooling rolls of the second cooling roll 7 and the third cooling roll 8 to be cooled and solidified Is referred to as a film (10). Subsequently, the film 10 peeled off by the peeling roll 9 is successively stretched in the width direction by grasping both end portions of the film by the stretching device 12, and then wound by the winding device 16. Further, in order to calibrate the flatness, a touch roll 6 for cooperating with the melted film on the surface of the first cooling roll 5 is provided. The touch roll 6 has elasticity on its surface and forms a gap with the first cooling roll 5. Details of the touch roll 6 will be described later.

In the method for producing a cellulose ester optical film according to the present invention, the conditions for melt extrusion may be the same as those used for other thermoplastic resins such as polyester. It is preferable to dry the material in advance. It is preferable to dry the water to 1000 ppm or less, preferably 200 ppm or less by using a vacuum or reduced pressure dryer or a dehumidifying hot air dryer.

For example, the cellulose ester-based resin dried under hot air or vacuum or reduced pressure is melted at an extrusion temperature of about 200 to 300 캜 using an extruder 1, and filtered with a lip disk type filter 2 or the like to remove foreign matter .

As a filter used for removing foreign matter, a stainless steel fiber sintered filter is preferably used. The stainless steel fiber sintering filter is formed by integrally forming a stainless steel fiber body into a state of being entangled with each other and then compressing and sintering the contact portions so that the filtration accuracy can be adjusted by changing the density depending on the thickness of the fiber and the amount of compression . It is preferable to use a multi-layer structure obtained by continuously repeating filtration precision several times. Further, it is preferable to employ a method of increasing the filtration accuracy sequentially or repeating the filtration accuracy or the repetition of the filtration, thereby increasing the filtration life of the filter and improving the replenishment accuracy of foreign matters and gel.

When it is introduced into the extruder 1 from a supply hopper (not shown), it is preferable to prevent the oxidative decomposition or the like under a vacuum or under reduced pressure or in an inert gas atmosphere.

If additives such as a plasticizer are not mixed in advance, they may be put in the middle of an extruder. It is preferable to use a mixing device such as a static mixer 3 in order to uniformly add it.

In the present invention, it is preferable that the cellulose resin and other additives such as stabilizers added as necessary are mixed before melting. It is more preferable to mix the cellulose resin and the stabilizer first. The mixing may be performed by a mixer or the like, or may be mixed in the process of preparing a cellulose resin as described above. When a mixer is used, a Henschel mixer, a ribbon mixer, and a general mixer may be used, such as a V-type mixer, a cone screw type mixer, a horizontal cylindrical mixer and the like.

After the film constituting materials are mixed as described above, the mixture may be directly melted by using the extruder 1, but once the film constituting material is pelletized, the pellets are melted by the extruder 1 It is also possible to form it. When the film constituting material contains a plurality of materials having different melting points, a semi-molten material having voids is once formed at a temperature at which only a material having a low melting point is melted and a semi-molten material is put into the extruder 1 It is also possible to form a film by this. When a film-forming material contains a material that is easily pyrolyzed, it is preferable to form the film directly without forming the pellet, or to form the semi-molten material having the voids as described above for the purpose of reducing the number of melts.

As the extruder 1, various extruders available on the market can be used, such as a melt-kneading extruder, and may be a single-screw extruder or a twin-screw extruder. When a film is directly formed without forming pellets from a film constituting material, it is preferable to use a twin screw extruder because an appropriate kneading degree is required. However, even with a single screw extruder, the shape of the screw can be changed into a multi- Or the like, so that appropriate kneading can be obtained, so that it can be used. When a semi-molten material having pellets or pores is used as the film constituting material, it can be used in a single-screw extruder or a twin-screw extruder.

The cooling step in the extruder 1 and after the extrusion is preferably carried out by reducing the oxygen concentration by replacing with an inert gas such as nitrogen gas or by reducing the pressure.

The melting temperature of the film constituting material in the extruder 1 differs depending on the preferable conditions depending on the viscosity and discharge amount of the film constituting material and the thickness of the sheet to be produced. Generally, the melting temperature of the film constituting material in the extruder 1, Tg or more and Tg + 100 占 폚 or less, preferably Tg + 10 占 폚 or more and Tg + 90 占 폚 or less. The melting temperature is usually in the range of 150 to 300 占 폚, preferably 180 to 270 占 폚, more preferably 200 to 270 占 폚. The melt viscosity at the time of extrusion is 1 to 10000 Pa · s, preferably 10 to 1000 Pa · s. The retention time of the film constituting material in the extruder 1 is preferably short, and is within 10 minutes, preferably within 5 minutes, more preferably within 3 minutes. The retention time depends on the type of the extruder 1 and the conditions under which the extruded material is extruded. However, the retention time can be shortened by adjusting the supply amount of the material, the L / D, the screw rotation speed,

The shape and rotation speed of the screw of the extruder 1 are appropriately selected depending on the viscosity of the film constituting material, the discharge amount, and the like. In the present invention, the shearing rate in the extruder 1 is 1 / sec to 10000 / sec, preferably 5 / sec to 1000 / sec, and more preferably 10 / sec to 100 / sec.

The extruder 1 usable in the present invention is generally available as a plastic molding machine.

The film constituting material extruded from the extruder 1 is sent to the flexible die 4 and extruded into a film form from the slit of the flexible die 4. The flexible die 4 is not particularly limited as long as it is used for producing a sheet or a film. The flexible die 4 may be formed by spraying or plating hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, ultra-high strength, ceramics (tungsten carbide, aluminum oxide, chromium oxide) Machining such as buffing, lapping using a grindstone after # 1000th, plane cutting using a diamond grindstone of # 1000 or more (cutting direction is a direction perpendicular to the flow direction of the resin), electrolytic polishing, And the like. The preferred material of the lip portion of the flexible die 4 is the same as the flexible die 4. The surface accuracy of the lip portion is preferably 0.5 S or less, more preferably 0.2 S or less.

The slit of the flexible die 4 is configured so that its gap can be adjusted. This is shown in Fig. Fig. 3 (a) is an outline view showing an example of a main portion of a flexible die, and Fig. 3 (b) is a sectional view showing an example of a main portion of a flexible die. One of the pair of lips forming the slit 32 of the flexible die 4 is a flexible lip 33 that is easily deformed with low rigidity and the other is a fixed lip 34. [ A plurality of heat bolts 35 are arranged at a constant pitch in the width direction of the flexible die 4, that is, the longitudinal direction of the slit 32. Each of the heat bolts 35 is provided with a block 36 having a buried electric heater 37 and a cooling medium passage and each heat bolt 35 vertically penetrates each block 36. The base of the heat bolt 35 is fixed to the die body 31 and its tip end is in contact with the outer surface of the flexible rib 33. [ The temperature of the block 36 is increased or decreased by increasing or decreasing the input of the buried electric heater 37 while the block 36 is always kept air-cooled. By this, the heat bolt 35 is thermally expanded and contracted, And the thickness of the film is adjusted by displacing it. The thickness measuring device is provided at a required position of the die wedge, and the detected web thickness information is fed back to the control device. The thickness information is compared with the setting thickness information in the control device, and by the signal of the correction control amount coming from the device The power or the warm-up rate of the heat-generating body of the heat-bolt may be controlled. The heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm and is arranged with a plurality of, for example, dozens of heat bolts, preferably at a pitch of 20 to 40 mm. Instead of the heat bolt, a gap adjusting member composed mainly of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided. The slit gap controlled by the gap adjusting member is usually 200 to 3000 占 퐉, preferably 500 to 2000 占 퐉.

The first to third cooling rolls are seamless steel tubes having a thickness of about 20 to 30 mm and the surface is finished to a mirror-finished surface. And a pipe for flowing a cooling liquid or a heating medium is disposed in the inside of the pipe so that heat can be absorbed or heated from the film on the roll by a cooling liquid flowing through the pipe or a heating medium.

On the other hand, the touch roll 6 contacting with the first cooling roll 5 has a surface elasticity and is deformed along the surface of the first cooling roll 5 by a pressing force against the first cooling roll 5 , And the first roll (5). The touch roll 6 is also referred to as a narrowing-down rotating body. As the touch roll 6, a touch roll disclosed in Japanese Patent No. 3194904, Japanese Patent No. 3422798, Japanese Patent Application Laid-Open No. 2002-36332, Japanese Patent Laid-Open No. 2002-36333, etc. can be preferably used. These may be commercially available. These will be described in more detail below.

Fig. 4 is a cross-sectional view showing an example of a squeeze rolling body (a schematic cross section of a first example (hereafter referred to as touch roll A) of the touch roll 6). As shown in the drawing, the touch roll A has an elastic roller 42 disposed inside a flexible metal sleeve 41.

The metal sleeve 41 is made of stainless steel having a thickness of 0.3 mm and has flexibility. If the metal sleeve 41 is too thin, the strength is insufficient. On the other hand, if the metal sleeve 41 is too thick, the elasticity is insufficient. Therefore, the thickness of the metal sleeve 41 is preferably 0.1 mm or more and 1.5 mm or less. The elastic roller 42 is formed in a roll shape by providing rubber 44 on the surface of a metal inner tube 43 rotatable through a bearing. When the touch roll A is pressed toward the first cooling roll 5, the elastic roller 42 pushes the metal sleeve 41 against the first cooling roll 5, and the metal sleeve 41 and the elastic roller 42 deform in correspondence with the shape conforming to the shape of the first cooling roll 5, and form a gap with the first cooling roll. In the space formed between the metal sleeve 41 and the elastic roller 42, the cooling water or the heating medium 45 flows.

5 is a cross-sectional view in a plane perpendicular to the rotation axis showing a second example (hereafter referred to as touch roll B) of the narrowing-down rotary body.

6 is a cross-sectional view showing an example of a plane including the rotation axis of the second example (touch roll B) of the narrowing-down rotary body.

5 and 6, the touch roll B is composed of an outer tube 51 made of a seamless stainless steel pipe (4 mm in thickness) having flexibility and a high rigidity metal And the inner cylinder 52 as shown in Fig. The cooling fluid or the heating medium 54 flows in the space 53 between the outer cylinder 51 and the inner cylinder 52. [ More specifically, the touch roll B is provided with outer tube supporting flanges 56a, 56b at both ends of the rotary shafts 55a, 55b, and a thin metal outer tube 51 is formed between the outer peripheral portions of the two tube outer tube supporting flanges 56a, Is installed. A fluid supply pipe 59 is disposed in the same axial center in the fluid discharge hole 58 formed in the axial center of the one rotary shaft 55a and forming the fluid return passage 57. The fluid supply pipe 59 And is fixedly connected to the fluid storage barrel 60 disposed at the axial center in the thin metal outer barrel 51. [ End support flanges 61a and 61b are provided at both ends of the fluid storage barrel 60 and the outer barrel support flanges 61b and 61b extend from the outer peripheral portion of the inner barrel support flanges 61a and 61b to the outer- The metal inner tube 52 having a thickness of about 1 mm is provided. A cooling fluid or a heating medium supply space 53 of about 10 mm or so is formed between the metal inner cylinder 52 and the thin metal outer cylinder 51, An outlet port 52a and an inlet port 52b for communicating the intermediate passages 62a and 62b outside the flow path space 53 and the inner tube support flanges 61a and 61b are formed respectively.

In addition, the outer cylinder 51 is made thinner within a range in which the thin cylindrical theory of elastic dynamics can be applied in order to have flexibility, flexibility, and stability close to rubber elasticity. The flexibility evaluated in this thin cylindrical theory is represented by the thickness t / roll radius r, and the smaller the t / r, the higher the flexibility. In this touch roll B, when t / r &amp;le; 0.03 is satisfied, the condition of flexibility is optimum. Generally, the touch roll generally has a roll diameter R = 200 to 500 mm (roll radius r = R / 2), a roll effective width L = 500 to 1600 mm, and a long shape with r / L &lt; 6, for example, when the roll diameter R is 300 mm and the roll effective width L is 1200 mm, the optimum range of the thickness t is 150 x 0.03 = 4.5 mm or less. However, when the width of the molten sheet is 1300 mm When the linear pressure is reduced to 100 N / cm, the thickness of the outer cylinder 51 is made to be 3 mm as compared with the rubber roll of the same shape, and a considerable spring constant is the same. The gap between the outer cylinder 51 and the cooling roll, (k) is about 9 mm, which is close to the gap width of about 12 mm, and it can be understood that the narrowing can be performed under the same conditions. The warpage in the gap width k is about 0.05 to 0.1 mm.

In the case of a general roll diameter R = 200 to 500 mm, in particular, when the range of 2 mm? T? 5 mm is satisfied, flexibility can be sufficiently obtained, and thinning by machining can be easily carried out And it becomes a very practical range.

The converted value of 2 mm? T? 5 mm is 0.008? T / r? 0.05 based on the general roll diameter. In practice, the thickness may be increased in proportion to the roll diameter under the condition of t / r? 0.03. For example, the roll diameter is selected in the range of t = 2 to 3 mm for R = 200 and t = 4 to 5 mm for R = 500.

The touch rolls A and B are biased toward the first cooling roll by a biasing means not shown. F / W (linear pressure) obtained by dividing the bias force of the bias means by the width W of the film in the gap along the rotation axis of the first cooling roll 5 is 10 N / cm or more and 150 N / cm. According to the present embodiment, a gap is formed between the touch rolls A and B and the first cooling roll 5, and the flatness can be corrected while the film passes through the gap. Therefore, compared with the case where the touch roll is made of a rigid body and a gap is not formed between the roll and the first cooling roll, the film is clamped at a low linear pressure for a long time, so that the flatness can be corrected more reliably. That is, if the line pressure is less than 10 N / cm, the die line can not be sufficiently removed. On the other hand, if the line pressure is higher than 150 N / cm, the film is difficult to pass through the gap, and the thickness of the film is rather uneven.

Further, by forming the surfaces of the touch rolls A and B with a metal, the surface of the touch rolls A and B can be made smoother than when the surface of the touch roll is rubber, so that a film having high smoothness can be obtained. As the material of the elastic body 44 of the elastic roller 42, ethylene propylene rubber, neoprene rubber, silicone rubber, or the like can be used.

In order to solve the die line well by the touch roll 6, it is important that the viscosity of the film when the touch roll 6 narrows the film is in an appropriate range. It is also known that the cellulose resin has a relatively large change in viscosity due to temperature. Therefore, in order to set the viscosity when the touch roll 6 narrows the cellulose ester optical film to an appropriate range, it is necessary to set the temperature of the film when the touch roll 6 narrows the cellulose ester optical film to an appropriate range It is important. When the glass transition temperature of the cellulose ester optical film is taken as Tg, the present inventors set the temperature T of the film just before the film is tightly pressed on the touch roll 6 to satisfy Tg <T <Tg + 110 ° C . If the film temperature T is lower than Tg, the viscosity of the film becomes higher. On the contrary, if the temperature T of the film is higher than Tg + 110 deg. C, there is a possibility that the film surface and the roll are not uniformly adhered, . Tg + 10 ° C <T <Tg + 90 ° C, more preferably Tg + 20 ° C <T <Tg + 70 ° C. In order to set the temperature of the film at the time when the touch roll 6 narrows the cellulose film to an appropriate range, the molten material extruded from the flexible die 4 is moved from the position P1 where it contacts the first cooling roll 5 to the first cooling The length L along the rotation direction of the first cooling roll 5 may be adjusted to the position P2 of the clearance between the roll 5 and the touch roll 6. [ Or the surface temperatures of the touch roll 6, the first cooling roll 5, the second cooling roll 7 and the third cooling roll 8 may be properly controlled. The surface temperature of the touch roll 6 and the first cooling roll 5 is preferably in the range of 60 to 230 캜 and more preferably in the range of 100 to 150 캜, The temperature is usually in the range of 30 to 150 占 폚, more preferably in the range of 60 to 130 占 폚.

In the present invention, preferable materials for the first roll 5 and the second roll 6 include carbon steel, stainless steel, and resin. The surface precision is preferably high, and the surface roughness is set to 0.3 S or less, more preferably 0.01 S or less.

The inventors of the present invention have found that the calibrating effect of the die line is more remarkably exhibited by reducing the pressure from the opening (lip) of the flexible die 4 to the first roll 5 to 70 kPa or less. Preferably, the reduced pressure is 50 kPa or more and 70 kPa or less. The method of keeping the pressure of the portion from the opening of the flexible die 4 to the first roll 5 at 70 kPa or less is not particularly limited but a method of covering the periphery of the roll with the pressure- There is a method of decompressing or the like. At this time, it is preferable that the suction device is subjected to treatment such as heating with a heater so that the device itself does not become an attachment place of the sublimate. In the present invention, when the suction pressure is excessively small, it is not possible to effectively suck up the entrained product, so it is necessary to set the suction pressure to a proper value.

In the present invention, the film-like cellulose ester resin in a molten state is supplied from the T die 4 to the first roll (first cooling roll) 5, the second cooling roll 7 and the third cooling roll 8 ), And cooled and solidified while being conveyed to obtain an unstretched cellulose ester based resin film (10).

In the embodiment of the present invention shown in Fig. 1, the cooled and solidified unstretched film 10 peeled off from the third cooling roll 8 by the peeling roll 9 is fed to the dancer roll (film tension adjusting roll) And is led to the stretching machine 12, where the film 10 is stretched in the transverse direction (width direction). By this stretching, molecules in the film are oriented.

As a method of stretching the film in the width direction, a known tenter or the like can be preferably used. Particularly, it is preferable that the stretching direction is set to the width direction so that the lamination with the polarizing film can be performed in the form of a roll. By stretching in the width direction, the slow axis of the cellulose ester optical film made of the cellulose ester based resin film becomes the width direction.

On the other hand, the transmission axis of the polarizing film is usually the width direction. By assembling the polarizing plate laminated so that the transmission axis of the polarizing film and the slow axis of the cellulose ester optical film are parallel to each other in the liquid crystal display device, the display contrast of the liquid crystal display device can be increased and a satisfactory viewing angle can be obtained.

The glass transition temperature (Tg) of the film constituting material can be controlled by making the proportion of the material constituting the film and the constituent material different. When a retardation film is produced as a cellulose ester optical film, it is preferable that the Tg is 110 deg. C or more, preferably 125 deg. C or more. In the liquid crystal display device, the temperature environment of the film changes due to the temperature rise of the apparatus itself, for example, the temperature rise from the light source, in the image display state. If the Tg of the film is lower than the environmental temperature of the film at this time, a large change is given to the retardation value derived from the orientation state of the molecules fixed in the film by stretching and the dimensional shape as the film. If the Tg of the film is excessively high, the temperature of the film constituting material becomes high when the film is made into a film, so that the energy consumption for heating is increased, and the decomposition of the material itself during film formation and coloring thereof may occur. 250 DEG C or less is preferable.

In the stretching step, known heat fixing conditions, cooling and relaxation treatment may be performed, or may be suitably adjusted so as to have the properties required for the objective optical film.

In order to impart the function of the phase film for enhancing the physical properties of the phase film and the viewing angle of the liquid crystal display device, the stretching process and the heat fixing process are appropriately selected and carried out. When the stretching process and the heat-setting process are included, the heating and pressing process of the present invention is performed before the stretching process and the heat-setting process.

When a retardation film is prepared as a cellulose ester optical film and the functions of the polarizing plate protective film are combined, it is necessary to control the refractive index. The refractive index control can be performed by a stretching operation and a stretching operation is a preferred method . Hereinafter, the stretching method will be described.

The stretching is performed by longitudinal stretching, transverse stretching, or a combination thereof. The longitudinal stretching can be performed by roll stretching (stretching in the longitudinal direction using two or more pairs of nip rolls at a higher speed on the exit side) or fixed end stretching (gripping both ends of the film, And stretching in the longitudinal direction) or the like. Further, transverse stretching can be performed by tenter stretching (stretching by grasping both ends of the film with a chuck and extending it in the transverse direction (direction perpendicular to the longitudinal direction)}.

These longitudinal stretching and transverse stretching may be performed singly (uniaxially stretching) or combined (biaxially stretching). In the case of biaxial stretching, it may be carried out in the order of the length and the width (sequential stretching) or simultaneously (simultaneous stretching). The elongation speed of longitudinal stretching and transverse stretching is preferably 10% / minute to 10000% / minute, more preferably 20% / minute to 1000% / minute, and still more preferably 30% / minute to 800% / minute . In the case of multi-stage drawing, the drawing speed indicates an average value of the drawing speeds of the respective stages. Following this stretching, it is also desirable to relax 0% to 10% in the longitudinal or transverse direction. After stretching, it is also preferable to heat-set at 150 to 250 캜 for 1 second to 3 minutes.

In the stretching process of the retardation film, necessary retardations Ro and Rt can be controlled by stretching 1.0 to 4.0 times in one direction of the cellulose resin and 1.01 to 4.0 times in a direction orthogonal thereto within the film plane. Here, Ro represents the in-plane retardation, and the difference between the refractive index in the longitudinal direction MD in the plane and the refractive index in the transverse direction TD is multiplied by the thickness. Rt represents the retardation in the thickness direction and the refractive index in the plane TD average) and the refractive index in the thickness direction multiplied by the thickness.

The stretching can be performed, for example, sequentially or simultaneously with respect to the longitudinal direction of the film and the direction orthogonal to the longitudinal direction of the film and the width direction thereof. In this case, if the stretching ratio in at least one direction is too small, a sufficient retardation can not be obtained. If the stretching ratio is too large, stretching becomes difficult and film breakage may occur.

The stretching in the biaxial directions orthogonal to each other is effective for putting the refractive indexes (nx, ny, nz) of the film in a predetermined range. Here, nx is the refractive index in the MD direction, ny is the refractive index in the width TD direction, and nz is the refractive index in the thickness direction.

For example, in the case of stretching in the melt softening direction, if the shrinkage in the width direction is excessively large, the value of nz becomes excessively large. In this case, it can be improved by suppressing the width shrinkage of the film or stretching it in the width direction. In the case of stretching in the width direction, the refractive index may sometimes be distributed in the width direction. This distribution may appear when the tenter method is used. It is considered that this phenomenon occurs when a film is stretched in the width direction, a shrinking force is generated in the center portion of the film, and the end portion is fixed, and is called a so-called bowing phenomenon . Even in this case, the bowing phenomenon can be suppressed by stretching in the flexible direction, and the distribution of the retardation in the width direction can be reduced.

By stretching in the biaxial directions orthogonal to each other, variations in film thickness of the resulting film can be reduced. If the film thickness variation of the retardation film is excessively large, the retardation is uneven, and unevenness such as coloration may be a problem when used in a liquid crystal display.

The film thickness variation of the cellulose resin film is preferably within a range of 占 3% and 占 1%. For the above-mentioned purposes, a method of stretching in mutually orthogonal biaxial directions is effective, and the stretching magnifications in the biaxial directions orthogonal to each other are respectively 1.0 to 4.0 times in the flexible direction and 1.01 to 4.0 Preferably in the range of 1.0 to 1.5 times in the flexible direction and 1.05 to 2.0 times in the width direction, in order to obtain a retardation value necessary for obtaining the retardation value.

When the absorption axis of the polarizer exists in the longitudinal direction, the transmission axis of the polarizer coincides with the width direction. In order to obtain a long polarizing plate, the retardation film is preferably stretched so as to obtain a retardation axis in the width direction.

In the case of using a cellulose resin that obtains positive birefringence with respect to stress, the slow axis of the retardation film can be imparted in the width direction by stretching in the width direction from the above-described constitution. In this case, in order to improve the display quality, it is preferable that the slow axis of the retardation film is in the width direction, and in order to obtain the aimed retardation value, it is preferable that the (stretching magnification in the width direction) It is necessary to satisfy the condition.

After the stretching, the end portion of the film is slit and cut by a slitter 13 to be a product, and then the film is subjected to a knurling process (embossing process) by a knurling device consisting of an embossing ring 14 and a back roll 15 ) Is wound around the both ends of the film and wound by the take-up machine 16 to prevent the sticking and scratches in the cellulose ester film (original wound body) F from being generated. As a method of machining a metal, a metal ring having a concavo-convex pattern on its side surface can be processed by heating or pressing. Further, the gripping portions of the clips at both ends of the film are usually deformed and can not be used as a film product, so they are cut and reused as a raw material.

In general, in the melt extrusion, it is known that the residence time at the end side tends to become longer due to the shape of the flexible die, thereby promoting the coloring of the film end portion. However, it has been found that the use of the production method of the film of the present invention inhibits the coloring of the film end portion. In the present invention, the yellow index Ye at the end portion in the film width direction immediately after melt extrusion and the yellow index Yc at the center portion of the film preferably satisfy the following expression (4), and more preferably Ye / Yc is 3.0 or less. If Ye / Yc is larger than 5.0, the end of the film is cut off, and when the film is reused as a raw material, the coloring of the produced film is increased. In the present invention, the yellow index at the end portion is defined as a maximum value within 30 mm from both ends in the film width direction.

<Formula 4>

1.0? Ye / Yc? 5.0

When the retardation film is a polarizing plate protective film, the thickness of the protective film is preferably 10 to 500 mu m. Particularly, the lower limit is 20 占 퐉 or more, preferably 30 占 퐉 or more. The upper limit is 150 mu m or less, preferably 120 mu m or less. A particularly preferable range is 25 to 90 占 퐉. If the retardation film is thick, the polarizing plate after the processing of the polarizing plate becomes too thick, so that the liquid crystal display used for a notebook computer or a mobile electronic apparatus is not particularly suitable for the purpose of being thin and lightweight. On the other hand, if the retardation film is thin, it is difficult to express retardation as a retardation film, and the moisture permeability of the film increases, and the ability of the polarizer to protect the polarizer from humidity tends to decrease.

When the slow axis or the fast axis of the phase difference film is present in the film plane and the angle formed with the film formation direction is? 1,? 1 is set to be -1 degrees or more + 1 degree or less, preferably -0.5 degrees or more + .

This? 1 can be defined as an orientation angle, and the measurement of? 1 can be performed using an automatic birefringence system KOBRA-21ADH (Prince Instruments).

? 1 respectively satisfy the above-described relation, contributing to suppressing or preventing light leakage and contributing to faithful color reproduction in a color liquid crystal display device.

When the cellulose ester optical film according to the present invention is used as a retardation film and is used in a multi-domain VA mode, the arrangement of the retardation film is improved by improving the display quality And the MVA mode as the polarizing plate and the liquid crystal display device, for example, the configuration shown in Fig. 7 can be taken.

In FIG. 7, reference numerals 21a and 21b denote protection films, reference numerals 22a and 22b denote retardation films, reference numerals 25a and 25b denote polarizers, reference numerals 23a and 23b denote retardation axes of the film, reference numerals 24a and 24b denote transmission axis directions of polarizers, 27 is a liquid crystal cell, and 29 is a liquid crystal display device.

The distribution of the retardation (Ro) in the in-plane direction of the optical film is preferably adjusted to 5% or less, more preferably 2% or less, and particularly preferably 1.5% or less. The distribution of the retardation (Rt) in the thickness direction of the film is preferably adjusted to 10% or less, more preferably 2.0% or less, and particularly preferably 1.5% or less.

In the retardation film, it is preferable that the variation of the distribution of the retardation value is small. When the polarizing plate including the retardation film is used in the liquid crystal display device, the retardation distribution fluctuation is preferably small in view of preventing color unevenness and the like.

In order to adjust the phase difference film to be suitable for the improvement of the display quality of the liquid crystal cell of the VA mode or the TN mode or to have the retardation value and to be preferably used in the MVA mode by dividing into the multi domain as VA mode in particular, It is required to adjust the retardation Ro to a value larger than 30 nm and smaller than 95 nm and a thickness direction retardation (Rt) larger than 70 nm and smaller than 400 nm.

The above-mentioned in-plane retardation (Ro) is a value obtained by observing in the normal direction of the display surface when two polarizing plates are arranged in Cross Nicole and the liquid crystal cell is arranged between the polarizing plates, for example, When viewed in a crossed Nicol state as a standard and obliquely observed on the normal of the display surface, a deviation from the crossed Nicol state of the polarizing plate occurs and mainly compensates for light leakage as a factor. The retardation in the thickness direction contributes mainly to compensate the birefringence of the liquid crystal cell recognized when viewed from the oblique plane when the liquid crystal cell is in the black display state in the TN mode or the VA mode, particularly, the MVA mode.

7, in the liquid crystal display device, when two polarizing plates are arranged on the upper and lower sides of the liquid crystal cell, 22a and 22b in the figure can select the distribution of the thickness direction retardation (Rt) And the total value of the retardation in the thickness direction (Rt) is preferably larger than 140 nm and not larger than 500 nm. The in-plane retardation (Ro) and the thickness direction retardation (Rt) of the polarizing plates 22a and 22b are preferably the same for improving the productivity of the industrial polarizing plate. Particularly preferably, the present invention is applied to a liquid crystal cell of the MVA mode in the configuration of Fig. 7, in which the in-plane retardation (Ro) is larger than 35 nm and is 65 nm or less and the thickness direction retardation (Rt) is larger than 90 nm and 180 nm or less.

In a liquid crystal display, for example, a TAC film having in-plane retardation Ro = 0 to 4 nm, retardation Rt in the thickness direction 20 to 50 nm and thickness 35 to 85 m as a commercially available polarizing plate protective film can be used, for example, 7, the polarizing film disposed on the other polarizing plate, for example, the retardation film disposed on the polarizing film 22a in Fig. 7, has an in-plane retardation Ro of 30 nm or more and 95 nm or less, Further, a retardation (Rt) in the thickness direction of more than 140 nm and not more than 400 nm is preferably used. The display quality is improved and the production of the film is also preferable.

(Polarizer)

The polarizer of the present invention will be described.

The polarizing plate can be manufactured by a general method. A fully saponified polyvinyl alcohol aqueous solution is applied to at least one surface of a polarizing membrane produced by alkali saponifying the back side of the cellulose ester optical film of the present invention and immersing and stretching the treated cellulose ester optical film in an iodine solution, . On the other side, the cellulose ester optical film of the present invention may be used, or another polarizing plate protective film may be used. With respect to the cellulose ester optical film of the present invention, a commercially available cellulose ester film can be used as the polarizing plate protective film used for the other side. For example, as a commercially available cellulose ester film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3 and KC8UCR-4 (manufactured by Konica Minolta Opto) are preferably used. It is also preferable to use a polarizing plate protective film serving also as an optical compensation film having an optically anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystals, rod-shaped liquid crystals and cholesteric liquid crystals. For example, an optically anisotropic layer can be formed by the method described in Japanese Patent Application Laid-Open No. 2003-98348. When used in combination with the antireflection film of the present invention, a polarizing plate excellent in planarity and having a stable viewing angle increasing effect can be obtained.

A polarizing film that is a main component of the polarizing plate is a device that allows only light of a polarization plane in a certain direction to pass. A typical polarizing film currently known is a polyvinyl alcohol polarizing film, which is obtained by dyeing a polyvinyl alcohol film with iodine And dyed dichromatic dyes. The polarizing film is formed by forming a polyvinyl alcohol aqueous solution, uniaxially stretching it, dyeing it, dyeing it, uniaxially stretching it, and then durably treating it with a boron compound. One side of the cellulose ester optical film of the present invention is bonded on the surface of the polarizing film to form a polarizing plate. Preferably, it is bonded by an aqueous adhesive mainly composed of fully saponified polyvinyl alcohol or the like.

Since the polarizing film is stretched in the uniaxial direction (usually, the longitudinal direction), if the polarizing plate is placed under an environment of high temperature and high humidity, the stretching direction (usually the longitudinal direction) is reduced and elongated in the stretching direction and the vertical direction (usually the width direction). The thinner the film thickness of the polarizing plate protective film, the larger the expansion / contraction ratio of the polarizing plate becomes, and particularly the larger the shrinking amount of the polarizing film in the stretching direction. Normally, the stretching direction of the polarizing film is bonded to the direction of orientation (MD direction) of the polarizing plate protective film. Therefore, in the case of thinning the polarizing plate protective film, it is particularly important to suppress the stretching ratio in the stretching direction. Since the optical film of the present invention is extremely excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.

That is, even in a durability test under the conditions of 60 占 폚 and 90% RH, the irregularity of the wave shape is not increased, and even in the case of the polarizing plate having the optical compensation film on the back side, the viewing angle characteristic does not fluctuate after the durability test, can do.

The polarizing plate may be constituted by bonding a protective film to one surface of the polarizing plate and a separate film to the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate when the polarizing plate is shipped, when the product is inspected, and the like. In this case, the protective film is bonded to protect the surface of the polarizing plate, and is used on the side opposite to the side joining the polarizing plate to the liquid crystal plate. The separate film is used for the purpose of covering the adhesive layer bonded to the liquid crystal plate, and is used on the side of bonding the polarizing plate to the liquid crystal cell.

(Liquid crystal display device)

The polarizing plate comprising the cellulose ester optical film according to the present invention as a retardation film can exhibit a higher display quality than a conventional polarizing plate and is particularly suitable for use in a multi-domain liquid crystal display device, more preferably a multi- And is suitable for use in a domain type liquid crystal display device.

The polarizing plate of the present invention can be used in a multi-domain vertical alignment (MVA) mode, a patterned vertical alignment (PVA) mode, a continuous pinwheel alignment (CPA) mode, an optical compensated bend But is not limited to the arrangement.

The liquid crystal display device is applied as a device for coloring and moving picture display, and the display quality is improved by the present invention, and the improvement of contrast and the resistance of the polarizing plate are improved, and faithful moving picture display can be achieved without becoming tired easily.

In the liquid crystal display device including at least the polarizing plate including the retardation film, one polarizing plate including the retardation film is disposed on the liquid crystal cell, or two polarizing plates are disposed on both sides of the liquid crystal cell. At this time, by using the phase difference side of the present invention included in the polarizing plate to face the liquid crystal cell of the liquid crystal display device, it is possible to contribute to improvement of the display quality. In Fig. 7, the films 22a and 22b face the liquid crystal cell of the liquid crystal display device.

In such a configuration, the retardation film can optically compensate the liquid crystal cell. When the polarizing plate of the present invention is used in a liquid crystal display device, at least one polarizing plate of the polarizing plate of the liquid crystal display device may be referred to as a polarizing plate of the present invention. By using the polarizing plate of the present invention, it is possible to provide a liquid crystal display device having improved display quality and excellent viewing angle characteristics.

In the polarizing plate of the present invention, a polarizing plate protective film of a cellulose derivative is used on the surface opposite to the retardation film as viewed from the polarizer, and a general-purpose TAC film or the like can be used. The polarizing plate protective film located on the side far from the liquid crystal cell can be provided with another functional layer after improving the quality of the display device.

For example, in order to prevent reflection, prevent glare, prevent scratches, prevent adhesion of contaminants and improve brightness, a film containing a known functional layer as a display material or a polarizing plate of the present invention may be adhered to the surface of the polarizing plate of the present invention, no.

In general, in the retardation film, fluctuation of Ro or Rt as the above retardation value is required in order to obtain stable optical characteristics. Particularly, in the liquid crystal display device of the birefringence mode, the fluctuation may cause the unevenness of the image.

According to the present invention, since the elongated retardation film produced by the melt softening method is composed mainly of a cellulose resin, the alkali treatment process can be utilized utilizing the inherent saponification of the cellulose resin. This is because when the resin constituting the polarizer is polyvinyl alcohol, it can be bonded to the elongated retardation film by using a fully saponified polyvinyl alcohol aqueous solution like the conventional polarizing plate protective film. Therefore, the present invention is superior in that it can apply the conventional polarizing plate processing method, and is particularly excellent in that a long-form roll polarizing plate can be obtained.

The manufacturing effect obtained by the present invention becomes more prominent especially in long rolls of 100 m or more, and the longer the length is, 1500 m, 2500 m, and 5000 m, the more the manufacturing effect of polarizing plate production is attained.

For example, in the production of a retardation film, the roll length is 10 m or more and 5000 m or less, preferably 50 m or more and 4500 m or less, considering the productivity and transportability. You can choose the appropriate width. A film may be prepared in a width of 0.5 m or more and 4.0 m or less, preferably 0.6 m or more and 3.0 m or less, and wound in a roll form to provide a polarizing plate. Further, And then cut to obtain a roll having a desired width, and these rolls may be used for polarizing plate processing.

A functional layer such as an antistatic layer, a hard coat layer, a self-lubricating layer, an adhesive layer, an anti-glare layer, or a barrier layer may be formed before and / or after the stretching of the cellulose ester optical film of the present invention. At this time, various surface treatments such as a corona discharge treatment, a plasma treatment, a chemical solution treatment, and the like can be carried out as needed.

In the film-forming step, the clip gripping portions at both ends of the cut film may be reused as raw materials for film of the same variety or as raw materials for film of other varieties after the pulverization treatment or, if necessary, after the granulation treatment.

It is also possible to produce a laminated optical film by co-extruding a composition containing a cellulose resin having a different additive concentration such as the plasticizer, ultraviolet absorber and matting agent described above. For example, an optical film having a constitution of a skin layer / a core layer / a skin layer can be produced. For example, the matting agent may be contained in the skin layer only or in the skin layer only. The plasticizer and ultraviolet absorber may be contained in the core layer more than the skin layer and may be incorporated only in the core layer. The kind of plasticizer and ultraviolet absorber may be changed in the core layer and the skin layer. For example, a low volatility plasticizer and / or an ultraviolet absorber may be contained in the skin layer so that a plasticizer having excellent plasticity or an ultraviolet absorptive This excellent ultraviolet absorber may be added. The glass transition temperature of the skin layer and the core layer may be different from each other and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer. At this time, the glass transition temperature of both the skin and the core may be measured, and the average value calculated from the volume fraction may be defined as the glass transition temperature (Tg). The viscosity of the melt containing the cellulose ester at the time of melt refining may also be different in the skin layer and the core layer, or the viscosity of the skin layer may be the viscosity of the core layer, or the viscosity of the core layer may be the viscosity of the skin layer.

The cellulose ester optical film of the present invention has a dimensional stability of less than +/- 2.0% in the dimensional change at 80 캜 and 90% RH on the basis of the dimension of the film left at 23 캜 and 55% RH for 24 hours, , Preferably less than 1.0%, and more preferably less than 0.5%.

When the cellulose ester optical film of the present invention is used as a retardation film and used as a protective film of a polarizing plate, if the retardation film itself has a variation of more than the above range, the absolute value of the retardation and the orientation angle as a polarizing plate deviate from the original setting , The ability to improve the display quality may be reduced or the display quality may be deteriorated.

The cellulose ester optical film of the present invention can be used for a polarizing plate protective film. When used as a polarizing plate protective film, the method of producing the polarizing plate is not particularly limited and can be manufactured by a general method. There is a method in which a polarizing plate protective film is bonded to both surfaces of a polarizer using a fully saponified polyvinyl alcohol aqueous solution on both sides of a polarizer produced by alkali treatment of the obtained cellulose ester optical film and immersion stretching of a polyvinyl alcohol film in an iodine solution , A cellulose ester optical film as a polarizing plate protective film of the present invention is directly bonded to at least one side of the polarizer.

Instead of the alkali treatment described above, the polarizing plate may be subjected to the bonding treatment described in JP-A-6-94915 and JP-A-6-118232.

(Formation of functional layer)

In the production of the optical film of the present invention, a functional layer such as a transparent conductive layer, a hard coat layer, an antireflection layer, an active layer, a bonding layer, an antiglare layer, a barrier layer and an optical compensation layer may be formed before and / In particular, it is preferable to provide at least one layer selected from a transparent conductive layer, a hard coat layer, an antireflection layer, a bonding layer, an antiglare layer and an optical compensation layer. At this time, various surface treatments such as a corona discharge treatment, a plasma treatment, a chemical solution treatment, and the like can be carried out as needed.

(Transparent conductive layer)

In the film of the present invention, it is also preferable to use a surfactant or a dispersion of conductive fine particles to provide a transparent conductive layer. The film itself may be provided with conductivity or a transparent conductive layer may be provided. In order to impart antistatic properties, it is preferable to provide a transparent conductive layer. The transparent conductive layer may be provided by coating, atmospheric pressure plasma treatment, vacuum deposition, sputtering, ion plating or the like. Alternatively, conductive fine particles may be contained only in the surface layer or the inner layer by a co-extrusion method to form a transparent conductive layer. The transparent conductive layer may be provided on only one side of the film or on both sides of the film. The conductive fine particles may be used in combination or in combination with a matting agent that imparts slidability. As the conductive agent, a metal oxide powder having the following conductivity can be used.

Examples of metal _{oxides, ZnO, TiO 2, SnO 2} , Al 2 0 3, I n2 O 3, such as SiO _2, MgO, BaO, Mo _O2, V ₂ O _5, or their composite oxide is preferred, and ZnO, TiO ₂ and SnO ₂ are preferable. For example, addition of Al, In or the like to ZnO, addition of Nb, Ta or the like to TiO ₂ , or addition of Sb, Nb, halogen element or the like to SnO ₂ is effective for an example including hetero atoms . The addition amount of these hetero atoms is preferably in the range of 0.01 to 25 mol%, but particularly preferably in the range of 0.1 to 15 mol%.

The conductive metal oxide powder preferably has a volume resistivity of 1 × 10 ⁷ Ω · cm, particularly 1 × 10 ⁵ Ω · cm or less, a primary particle diameter of 10 nm or more and 0.2 μm or less, a long diameter of a high- It is preferable that the conductive layer contains a powder having a specific structure of not more than 6 mu m in a volume fraction of not less than 0.01% and not more than 20%.

In the present invention, the transparent conductive layer may be formed by dispersing the conductive fine particles in a binder and forming the transparent conductive layer on the substrate. Alternatively, the transparent conductive layer may be undercoated on the substrate, and the conductive fine particles may be deposited thereon.

The ionic conductive polymer represented by the general formulas (I) to (V) described in paragraphs [0038] to [0055] of Japanese Patent Application Laid-Open No. 9-203810 or the ionic conductive polymer represented by the general formula Quaternary ammonium cationic polymer may be contained.

A heat resistant agent, an after-treatment agent, an inorganic particle, a water-soluble resin, an emulsion or the like may be added to the transparent conductive layer made of a metal oxide for the purpose of improving the matting and improving the film quality, without hindering the effect of the present invention.

The binder used in the transparent conductive layer is not particularly limited as long as it has film-forming ability, and examples thereof include proteins such as gelatin and casein, carboxymethylcellulose, hydroxyethylcellulose, acetylcellulose, diacetylcellulose, Cellulose derivatives such as dextran, agar, sodium alginate and starch derivatives, polyvinyl alcohols, polyvinyl acetate, polyacrylic esters, polymethacrylic esters, polystyrenes, polyacrylamides, poly-N- And synthetic polymers such as polystyrene, polyvinyl chloride, polyacrylic acid, and the like.

Particularly, it is possible to use gelatin (lime-processed gelatin, acid-treated gelatin, oxygenated gelatin, phthalated gelatin, acetylated gelatin and the like), acetylcellulose, diacetylcellulose, triacetylcellulose, polyvinyl acetate, polyvinyl alcohol, Acrylamide, dextran and the like are preferable.

(Antireflection film)

It is also preferable that the cellulose ester optical film of the present invention is provided with a hard coat layer and an antireflection layer on its surface to form an antireflection film.

As the hard coat layer, an active line cured resin layer or a thermosetting resin layer is preferably used. The hard coat layer may be formed directly on the support, or may be formed on another layer such as an antistatic layer or an undercoat layer.

When the active layer is formed as a hard coat layer, it preferably contains an actinic ray curable resin which is cured by light irradiation such as ultraviolet rays.

The hard coat layer preferably has a refractive index in the range of 1.45 to 1.65 from the viewpoint of optical design. From the viewpoints of imparting sufficient durability and impact resistance to the antireflection film, and also taking into consideration the appropriate bending property and economical efficiency at the time of production, the film thickness of the hard coat layer is preferably in the range of 1 m to 20 m, Lt; RTI ID = 0.0 &gt; 10 &lt; / RTI &gt;

The active ray-curable resin layer is a layer in which various electromagnetic waves such as an electron beam, a neutron beam, an X-ray, an alpha ray, an ultraviolet ray, a visible ray, an infrared ray, etc., Is defined as a layer containing a resin cured through a crosslinking reaction or the like as a main component. Examples of the actinic ray-curable resin include ultraviolet ray-curable resin and electron beam-curable resin, which may be cured by irradiation with light other than ultraviolet ray or electron beam. Examples of the ultraviolet ray curable resin include an ultraviolet ray curing type acryl urethane type resin, an ultraviolet ray curable type polyester acrylate type resin, an ultraviolet ray curing type epoxy acrylate type resin, an ultraviolet ray curing type polyol acrylate type resin or an ultraviolet ray curable type epoxy resin .

In addition, a photoreaction initiator and a photosensitizer may be contained. Specific examples thereof include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone,? -Amyloxime ester, thioxanthone, and derivatives thereof. When a photoreactive agent is used for the synthesis of the epoxy acrylate resin, a sensitizer such as n-butylamine, triethylamine or tri-n-butylphosphine may be used. It is preferable that the photoinitiator or photosensitizer contained in the ultraviolet-curable resin composition excluding the volatile solvent component after the application and drying is 2.5 to 6% by mass of the composition.

Examples of the resin monomer include monomers having one unsaturated double bond and common monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, vinyl acetate, benzyl acrylate, cyclohexyl acrylate and styrene. have. Examples of the monomer having two or more unsaturated double bonds include ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethylacrylate, Trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and the like.

The ultraviolet ray absorbing resin composition may also contain an ultraviolet absorbing agent to such an extent as not to hinder the active ray curing of the ultraviolet ray curable resin composition. As the ultraviolet absorber, the same ultraviolet absorber that may be used for the substrate may be used.

Further, in order to increase the heat resistance of the cured layer, an antioxidant that does not inhibit the active ray curing reaction can be selected and used. Examples thereof include hindered phenol derivatives, thiopropionic acid derivatives, and phosphite derivatives. Specific examples thereof include 4,4'-thiobis (6-t-3-methylphenol), 4,4'-butylidenebis (6-t- (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 2,4,6-tris ) Mesitylene, di-octadecyl-4-hydroxy-3,5-di-t-butylbenzyl phosphate and the like.

KR-400, KR-410, KR-550, KR-566, KR-567 and BY-320B (trade names, manufactured by Asahi Denka Kogyo A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T- PHCX-9 (K-1), NS-101, FT-102Q8, MAG-1-P20, AG-106 and M-101- 3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (manufactured by Daiichi Seika Kogyo K.K.), KRM7033, KRM7039, KRM7130 RC-5122, RC-5021, RC-5031, RC-5100, RC-5102, RC-5120, RCEC-5120, UVECRYL29201, UVECRYL29202 (above, Daicel UCB) (Available from Dainippon Ink and Chemicals, Inc.), RC-5152, RC-5171, RC-5180 and C-5181 (Manufactured by Sanyo Chemical Industries, Ltd.), SP-1509, SP-1507 (manufactured by Showa Highpolymer Co., Ltd.), RCC-15C (Grace Co., Bus may be used by appropriately selecting from M-6100, M-8030, M-8060 (above, doah Gosei Co., Ltd.) or those that are commercially available outside.

The coating composition for the active ray-curable resin layer preferably has a solid content concentration of 10 to 95 mass%, and a suitable concentration is selected by a coating method.

As the light source for forming the cured coating layer by the active ray curing reaction of the active ray curable resin, any light source that generates ultraviolet rays can be used. Specifically, the light source described in the above light section can be used. The irradiation conditions vary depending on the respective lamps, but the irradiation light amount is preferably in the range of 20 mJ / cm ² to 10000 mJ / cm ² , more preferably 50 mJ / cm ² to 2,000 mJ / cm ² . It can be used by using a sensitizer having an absorption maximum in the region from the near ultraviolet ray region to the visible ray region.

The solvent for forming the active ray-curable resin layer may be, for example, a hydrocarbon such as toluene or xylene, an alcohol such as methanol, ethanol, isopropanol, butanol or cyclohexanol, a ketone such as acetone, methyl ethyl ketone, methyl Isobutyl ketone), ketone alcohols (diacetone alcohol), esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers and other organic solvents, or a mixture thereof. More preferably 5 to 80 mass% of propylene glycol monoalkyl ether (1 to 4 carbon atoms in the alkyl group) or propylene glycol monoalkyl ether acetic acid ester (1 to 4 in number of carbon atoms of the alkyl group) % Or more of the organic solvent.

As the application method of the active ray-curable resin composition coating liquid, known methods such as a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater and an air doctor coater can be used. The application amount of the wet film is suitably from 0.1 m to 30 m, preferably from 0.5 m to 15 m. The coating speed is preferably in the range of 10 m / min to 60 m / min.

The active ray-curable resin composition is applied and dried and then irradiated with ultraviolet rays. The irradiation time is preferably 0.5 seconds to 5 minutes, more preferably 3 seconds to 2 minutes in terms of curing efficiency and working efficiency of the ultraviolet ray curable resin.

In order to provide an anti-glare function to the surface of the liquid crystal display panel and to prevent adhesion to other materials and to improve scratch resistance and the like, a cured coating layer can be obtained in the coating composition for a cured coating layer Inorganic or organic fine particles may be added.

For example, examples of the inorganic fine particles include silicon oxide, titanium oxide zirconium oxide, aluminum oxide, tin oxide, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin and calcium sulfate.

Examples of the organic fine particles include polymethacrylate methyl acrylate resin powder, acryl styrene resin powder, polymethyl methacrylate resin powder, silicone resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin Based resin powder, a melamine-based resin powder, a polyolefin-based resin powder, a polyester-based resin powder, a polyamide-based resin powder, a polyimide-based resin powder or a polyfluorinated ethylene resin powder. These can be used in addition to the ultraviolet ray curable resin composition. The average particle size of these fine particle powders is preferably 0.01 to 10 μm, and the amount of the fine particles to be used is preferably 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of the ultraviolet ray hardening resin composition. In order to provide an anti-glare effect, it is preferable to use 1 part by mass to 15 parts by mass of fine particles having an average particle diameter of 0.1 to 1 占 퐉 with respect to 100 parts by mass of the ultraviolet ray hardening resin composition.

By adding such fine particles to the ultraviolet curing resin, it is possible to form an anti-glare layer having a desired unevenness of the center line average surface roughness (Ra) of 0.05 to 0.5 占 퐉. When such fine particles are not added to the ultraviolet ray hardening resin composition, a center line average surface roughness (Ra) is less than 0.05 占 퐉, more preferably 0.002 占 퐉 to less than 0.04 占 퐉, and a hard coat layer having a good smooth surface is formed can do.

In addition, 0.1 part by mass to 5 parts by mass of the ultrafine particles having a volume average particle diameter of 0.005 占 퐉 to 0.1 占 퐉 relative to 100 parts by mass of the resin composition may be used to achieve the anti-blocking function.

The antireflection layer is provided on the hard coat layer, but the method is not particularly limited and may be formed by coating, sputtering, vapor deposition, CVD (Chemical Vapor Deposition), atmospheric pressure plasma, or a combination thereof. In the present invention, it is particularly preferable to provide an antireflection layer by coating.

Examples of the method of forming the antireflection layer by coating include a method of dispersing a powder of a metal oxide in a binder resin dissolved in a solvent, followed by coating and drying, a method of using a polymer having a crosslinked structure as a binder resin, a method of using an ethylenically unsaturated monomer and a photopolymerization initiator And a method of forming a layer by irradiating an active ray can be mentioned.

In the present invention, an antireflection layer can be provided on a cellulose ester optical film provided with an ultraviolet curing resin layer. A low refractive index layer is formed on the uppermost layer of the optical film, a metal oxide layer of a high refractive index layer is formed therebetween, and a medium refractive index layer (a content of a metal oxide or a resin binder And a metal oxide layer in which the refractive index is adjusted by changing the kind of the metal) is preferable for reducing the reflectance. The refractive index of the high refractive index layer is preferably 1.55 to 2.30, more preferably 1.57 to 2.20. The refractive index of the medium refractive index layer is adjusted to be a middle value between the refractive index (about 1.5) of the cellulose ester film as the base material and the refractive index of the high refractive index layer. The refractive index of the medium refractive index layer is preferably 1.55 to 1.80. The thickness of each layer is preferably from 5 nm to 0.5 μm, more preferably from 10 nm to 0.3 μm, and most preferably from 30 nm to 0.2 μm. The haze of the metal oxide layer is preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. The strength of the metal oxide layer is preferably 3H or more, more preferably 4H or more, in terms of pencil hardness under a load of 1 kg. In the case of forming the metal oxide layer by coating, it is preferable to include the inorganic fine particles and the binder polymer.

The middle and high refractive index layers in the present invention are preferably layers having a refractive index of 1.55 to 2.5 formed by applying and drying a coating liquid containing a monomer, an oligomer or a hydrolyzate thereof of an organic titanium compound represented by the following formula .

Ti (OR1) ₄

In formula (T), R1 is preferably an aliphatic hydrocarbon group of 1 to 8 carbon atoms, preferably an aliphatic hydrocarbon group of 1 to 4 carbon atoms. Further, the monomer, oligomer or hydrolyzate thereof of the organic titanium compound undergoes hydrolysis and reacts with -Ti-O-Ti- to form a crosslinked structure to form a cured layer.

As monomers, oligomers of the organic titanium compound used in the present _{invention, Ti (OCH 3) 4,} Ti (OC 2 H 5) 4, Ti (OnC 3 H 7) 4, Ti (OiC 3 H 7) 4, Ti _{(OnC 4 H 9) 4,} Ti (OnC 3 H 7) 2 and 10-mer of _{4, Ti (OiC 3 H 7} ) 2 and 10-mer of _{4, Ti (OnC 4 H 9} ) such as ₄₂ to 10-mer of As a preferable example. These may be used alone or in combination of two or more. Among them, _{Ti (OnC 3 H 7) 4} , Ti (OiC 3 H 7) 4, Ti (OnC 4 H 9) 4, Ti (OnC 3 H 7) 2 and 10-mer of _{4, Ti (OnC 4 H 9} ) ₄ to 2-to-10-isomers are particularly preferable.

In the present invention, it is preferable that the organic titanium compound is added to a solution in which water and an organic solvent described later are added in order, as a coating liquid for a medium and high refractive index layer. When water is added later, hydrolysis / polymerization may not proceed uniformly, clouding may occur, or the film strength may be lowered. It is preferable that water and an organic solvent are mixed and dissolved after being added and stirred for good mixing.

As another method, it is also preferable to mix the organic titanium compound with an organic solvent and add the mixed solution to the mixed solution of the water and the organic solvent.

The amount of water is preferably in the range of 0.25 to 3 moles per 1 mole of the organic titanium compound. If it is less than 0.25 mol, progress of hydrolysis and polymerization may be insufficient and the film strength may be lowered. If it exceeds 3 mol, the hydrolysis and polymerization proceed too much, and coarse particles of TiO ₂ may be generated and become cloudy. Therefore, the amount of water is preferably adjusted within the above range.

The content of water is preferably less than 10% by mass based on the total amount of the coating liquid. If the content of water is 10% by mass or more based on the total amount of the coating liquid, the coating liquid may become stale over time and clouding may occur.

The organic solvent used in the present invention is preferably an organic solvent which is water-miscible. Examples of water-miscible organic solvents include alcohols (e.g., alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, , Benzyl alcohol and the like), polyhydric alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin (E.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, Ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol mono Ethylene glycol monomethyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amines (e.g., ethanolamine, diethanolamine, triethanolamine, N- Methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethyl Propylenediamine and the like), amides (for example, formamide, N, N-dimethylformamide and N, N-dimethylacetamide), complex reflux 2-imidazolidinone, etc.), sulfoxides (e.g., dimethylsulfoxide and the like), sulfones (e.g., For example, sulforan, etc.), urea, Acetonitrile, acetone, etc. may, in particular, is preferably alcohols, polyhydric alcohols, polyhydric alcohol ethers. The amount of these organic solvents to be used may be adjusted by adjusting the total amount of water and the organic solvent so that the water content is less than 10 mass% with respect to the total amount of the coating liquid, as described above.

When used alone, the monomers, oligomers or hydrolyzates thereof of the organic titanium compound used in the present invention preferably account for 50.0% by mass to 98.0% by mass of solids contained in the coating liquid. The solid content ratio is more preferably 50% by mass to 90% by mass, and still more preferably 55% by mass to 90% by mass. In addition, it is also preferable to add a polymer of an organic titanium compound (which is obtained by hydrolyzing an organic titanium compound in advance and crosslinked) or titanium oxide fine particles to the coating composition.

The high refractive index layer and the medium refractive index layer in the present invention may contain metal oxide particles as fine particles and may also contain a binder polymer.

When the organic titanium compound hydrolyzed / polymerized by the coating liquid preparation method is combined with the metal oxide particles, the metal oxide particles and the hydrolyzed / polymerized organic titanium compound are firmly adhered to each other, and the hardness of the particles and the flexibility of the uniform film A coating film can be obtained.

The refractive index of the metal oxide particles used in the high refractive index layer and the medium refractive index layer is preferably 1.80 to 2.80, more preferably 1.90 to 2.80. The average particle diameter of the primary particles of the metal oxide particles is preferably 1 to 150 nm, more preferably 1 to 100 nm, and most preferably 1 to 80 nm. The average particle diameter of the metal oxide particles in the layer is preferably from 1 to 200 nm, more preferably from 5 to 150 nm, even more preferably from 10 to 100 nm, most preferably from 10 to 80 nm. The average particle diameter of the metal oxide particles can be determined by, for example, observing with a scanning electron microscope and measuring the long diameter of 200 particles randomly. The specific surface area of the metal oxide particles is, as a value measured by the BET method, is from 10 to 400m ² / g is preferable, and 20 to 200m ² / g is more preferred, and 30 to 150m ² / g is most preferred .

Examples of the metal oxide particles include at least one element selected from Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, Specific examples thereof include titanium dioxide (for example, mixed crystal of rutile, rutile / anatase, anatase, amorphous structure), tin oxide, indium oxide, zinc oxide and zirconium oxide. Of these, titanium oxide, tin oxide and indium oxide are particularly preferable. The metal oxide particles may contain oxides of these metals as a main component and further include other elements. The main component means a component having the largest content (mass%) among the components constituting the particles. Examples of other elements include Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S.

The metal oxide particles are preferably surface-treated. The surface treatment can be carried out using an inorganic compound or an organic compound. Examples of the inorganic compound used for the surface treatment include alumina, silica, zirconium oxide and iron oxide. Among them, alumina and silica are preferable. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents and titanate coupling agents. Among them, a silane coupling agent is most preferable.

Specific examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxy Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, gamma -chloropropyl Trimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, ? - (? - glycidyloxyethoxy) propyltrimethoxysilane,? - (3,4-epoxycyclohexyl) ethyltrimethoxysilane,? - 3,4-epoxycyclohexyl) ethyl triethoxysilane,? -Acryloyl Aminopropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma -mercaptopropyltrimethoxysilane, gamma -methacryloyloxypropyltrimethoxysilane, gamma -aminopropyltrimethoxysilane, gamma -aminopropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma- -Mercaptopropyltriethoxysilane, N -? - (aminoethyl) -? - aminopropyltrimethoxysilane and? -Cyanoethyltriethoxysilane.

Examples of the silane coupling agent having a 2-substituted alkyl group for silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, gamma -glycidyloxypropylmethyldiethoxy Silane,? -Glycidyloxypropylmethyldimethoxysilane,? -Glycidyloxypropylphenyldiethoxysilane,? -Chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane,? -Acryloyloxypropylmethyl Dimethoxysilane,? -Acryloyloxypropylmethyldiethoxysilane,? -Methacryloyloxypropylmethyldimethoxysilane,? -Methacryloyloxypropylmethyldiethoxysilane,? -Mercaptopropylmethyldimethoxy Silane, γ-mercaptopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane and methylvinyldiethoxysilane. .

Of these, vinyltrimethoxysilane having a double bond in the molecule, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, gamma -acryloyloxypropyltrimethoxysilane and gamma -metal Acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxymethylsiloxane, γ-acryloyloxypropylmethyldimethoxysilane, and γ- Acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferable, and γ-acryloyloxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are preferable, Acryloyloxypropyltrimethoxysilane,? -Acryloyloxypropylmethyldimethoxysilane,? -Acryloyloxypropylmethyldiethoxysilane,? -Methacryloyloxypropylmethyldimethoxysilane,? -Methacryloyloxypropylmethyldimethoxysilane, And gamma-methacryloyloxypropylmethyldiethoxysilane are particularly preferable.

Two or more kinds of coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicic acid (for example, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, t-butyl) and hydrolyzates thereof. The surface treatment with the coupling agent can be carried out by adding a coupling agent to the dispersion of the fine particles and allowing the dispersion to stand at a temperature from room temperature to 60 degrees for several hours to several days. In order to accelerate the surface treatment reaction, it is preferable to use an inorganic acid (e.g., sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, , Polyglutamic acid) or a salt thereof (e.g., metal salt, ammonium salt) may be added to the dispersion.

These silane coupling agents are preferably hydrolyzed in advance with a necessary amount of water. When the silane coupling agent is hydrolyzed, the surfaces of the organic titanium compound and the metal oxide particles described above are easily reacted to form a more rigid film. It is also preferable to add the hydrolyzed silane coupling agent in advance to the coating liquid. The water used for this hydrolysis can also be used for the hydrolysis / polymerization of the organic titanium compound.

In the present invention, two or more kinds of surface treatments may be combined and processed. The shape of the metal oxide particles is preferably in the form of fine particles, spherical shape, cubic shape, spindle shape or irregular shape. Two or more kinds of metal oxide particles may be used in combination with the high refractive index layer and the medium refractive index layer.

The proportion of the metal oxide particles in the high refractive index layer and the medium refractive index layer is preferably 5 to 90 mass%, more preferably 10 to 85 mass%, and still more preferably 20 to 80 mass%. When the fine particles are contained, the proportion of the monomer, oligomer or hydrolyzate thereof of the above-mentioned organic titanium compound is 1 to 50 mass%, preferably 1 to 40 mass%, more preferably 1 to 50 mass% Preferably 1 to 30% by mass.

The metal oxide particles are provided in a coating liquid for forming a high refractive index layer and a medium refractive index layer in the form of a dispersion dispersed in a medium. As the dispersion medium of the metal oxide particles, it is preferable to use a liquid having a boiling point of 60 to 170 캜. Specific examples of the dispersion solvent include water, alcohols (e.g., methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone) (For example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (e.g., hexane, cyclohexane), halogenated hydrocarbons Methylene chloride, chloroform, carbon tetrachloride), aromatic hydrocarbons (e.g. benzene, toluene, xylene), amides (e.g. dimethylformamide, dimethylacetamide, n-methylpyrrolidone) , Diethyl ether, dioxane, tetrahydrofuran), and ether alcohols (for example, 1-methoxy-2-propanol). Among them, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

Further, the metal oxide particles can be dispersed in the medium using a dispersing machine. Examples of the dispersing machine include a sand grinder mill (for example, a pin bead mill), a high-speed impeller mill, a pebble mill, a roller mill, an attritor and a colloid mill. Sand grinder mills and high-speed impeller mills are particularly preferred. In addition, preliminary dispersion treatment may be performed. Examples of the dispersing machine used for the preliminary dispersion treatment include a ball mill, a three-axis roll mill, a kneader and an extruder.

The high refractive index layer and the medium refractive index layer in the present invention preferably use a polymer having a crosslinked structure (hereinafter also referred to as a crosslinked polymer) as a binder polymer. Examples of the crosslinked polymer include crosslinked polymers such as polymers having saturated hydrocarbon chains such as polyolefins (hereinafter collectively referred to as polyolefins), polyethers, polyureas, polyurethanes, polyesters, polyamines, polyamides and melamine resins have. Among them, crosslinked products of polyolefins, polyethers and polyurethanes are preferable, crosslinked products of polyolefins and polyethers are more preferable, and crosslinked products of polyolefins are most preferred. Further, it is more preferable that the crosslinked polymer has an anionic group. The anionic group has a function of maintaining the dispersed state of the inorganic fine particles, and the crosslinked structure has a function of strengthening the coating by imparting film forming ability to the polymer. The anionic group may be directly bonded to the polymer chain or may be bonded to the polymer chain through a linking group, and it is preferable that the anionic group is bonded to the main chain as a side chain through a linking group.

Examples of the anionic group include a carboxylic acid group (carboxyl), a sulfonic acid group (sulfo) and a phosphoric acid group (phosphono). Among them, a sulfonic acid group and a phosphoric acid group are preferable. Here, the anionic group may be in a salt state. The cation forming the salt with the anionic group is preferably an alkali metal ion. The proton of the anionic group may be decomposed. The linking group for bonding the anionic group and the polymer chain is preferably a divalent group selected from -CO-, -O-, an alkylene group, an arylene group, and a combination thereof. It is preferable that the crosslinked polymer which is an aspending binder polymer is a copolymer having a repeating unit having an anionic group and a repeating unit having a crosslinking structure. In this case, the proportion of the repeating unit having an anionic group in the copolymer is preferably 2 to 96 mass%, more preferably 4 to 94 mass%, and most preferably 6 to 92 mass%. The repeating unit may have two or more anionic groups.

The crosslinked polymer having an anionic group may contain other repeating units (repeating units having no anionic, airway crosslinking structure). As the other repeating unit, a repeating unit having an amino group or a quaternary ammonium group and a repeating unit having a benzene ring are preferable. The amino group or the quaternary ammonium group has a function of maintaining the dispersed state of the inorganic fine particles like the anionic group. The benzene ring has a function of increasing the refractive index of the high refractive index layer. The same effect can be obtained even when the amino group, the quaternary ammonium group and the benzene ring are contained in the repeating unit having an anionic group or in the repeating unit having a crosslinking structure.

In the crosslinked polymer containing the repeating unit having an amino group or a quaternary ammonium group as a constitutional unit, the amino group or the quaternary ammonium group may be bonded directly to the polymer chain or may be bonded to the polymer chain as a side chain via a linking group , The latter being more preferable. The amino group or quaternary ammonium group is preferably a secondary amino group, a tertiary amino group or a quaternary ammonium group, more preferably a tertiary amino group or a quaternary ammonium group. The group bonded to the nitrogen atom of the secondary amino group, tertiary amino group or quaternary ammonium group is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, and still more preferably an alkyl group having 1 to 6 carbon atoms. The counter ion of the quaternary ammonium group is preferably a halide ion. The linking group for bonding the amino group or the quaternary ammonium group to the polymer chain is preferably a divalent group selected from -CO-, -NH-, -O-, alkylene group, arylene group, and combinations thereof. When the crosslinked polymer contains a repeating unit having an amino group or a quaternary ammonium group, the proportion thereof is preferably 0.06 to 32 mass%, more preferably 0.08 to 30 mass%, and more preferably 0.1 to 28 mass% Most preferred.

It is preferable that the crosslinked polymer is formed by preparing a coating liquid for forming a high refractive index layer and a medium refractive index layer by adding a monomer for producing a crosslinked polymer and by a polymerization reaction after or simultaneously with the application of the coating liquid. With the generation of the crosslinked polymer, each layer is formed. The monomer having an anionic group functions as a dispersing agent for the inorganic fine particles in the coating liquid. The amount of the monomer having an anionic group is preferably from 1 to 50 mass%, more preferably from 5 to 40 mass%, and even more preferably from 10 to 30 mass% with respect to the inorganic fine particles. Further, the monomer having an amino group or a quaternary ammonium group functions as a dispersing aid in the coating liquid. The monomer having an amino group or a quaternary ammonium group is preferably used in an amount of 3 to 33 mass% with respect to the monomer having an anionic group. These monomers can be effectively functioned before application of the coating liquid by a method of producing a crosslinked polymer by a polymerization reaction after or simultaneously with the application of the coating liquid.

As the monomer used in the present invention, monomers having two or more ethylenic unsaturated groups are most preferable. Examples thereof include esters of a polyhydric alcohol and (meth) acrylic acid (for example, ethylene glycol di (meth) acrylate (Meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylol ethane tri (meth) acrylate, pentaerythritol tri (meth) (Meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexane tetramethacrylate, polyurethane poly Acrylate, polyester polyacrylate), vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, Carbonyl cyclohexanone), vinyl sulfones (e.g., divinyl sulfone, and the like), acrylamides (e.g., methylenebisacrylamide) and methacrylamide. Monomers having an anionic group and monomers having an amino group or a quaternary ammonium group may be commercially available monomers. Examples of commercially available monomers having anionic groups include KAYAMARPM-21, PM-2 (manufactured by Nippon Kayaku), AntoxMS-60, MS-2N and MS-NH4 (Available from Osaka Organic Chemical Industry Co., Ltd.), New Frontier GX-8289 (manufactured by Dai-Ichi Kasei Kogyo K.K.), Arconics M-5000, M- AR-100, MR-100 and MR-200 (products of the 8th Chemical Industry Co., Ltd.), etc.), NK ester CB-1 and A-SA (manufactured by Shin Nakamura Chemical Industry Co., Ltd.) . Examples of commercially available monomers having an amino group or a quaternary ammonium group include DMAA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), DMAEA, DMAPAA (manufactured by Kouzin), and Bremer QA ), New Frontier C-1615 (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and the like.

The polymerization reaction of the polymer may be a photopolymerization reaction or a thermal polymerization reaction. Particularly preferred is a photopolymerization reaction. It is preferable to use a polymerization initiator for the polymerization reaction. For example, a thermal polymerization initiator and a photopolymerization initiator, which will be described below, which are used for forming a binder polymer of the hard coat layer, can be mentioned.

A commercially available polymerization initiator may be used as the polymerization initiator. A polymerization promoter may be used in addition to the polymerization initiator. The addition amount of the polymerization initiator and the polymerization promoter is preferably in the range of 0.2 to 10% by mass relative to the total amount of the monomers. The polymerization of monomers (or oligomers) may be promoted by heating the coating liquid (dispersion of the inorganic fine particles containing monomers). Further, the thermosetting reaction of the formed polymer may be further treated by heating after the photopolymerization reaction after the application.

It is preferable to use a polymer having a relatively high refractive index for the medium refractive index layer and the high refractive index layer. Examples of the polymer having a high refractive index include polyurethanes obtained by the reaction of polystyrene, a styrene copolymer, a polycarbonate, a melamine resin, a phenol resin, an epoxy resin, and a cyclic (alicyclic or aromatic) isocyanate and a polyol. Polymers having other cyclic (aromatic, heterocyclic, or alicyclic) groups or polymers having halogen atoms other than fluorine as substituents can also be used because of their high refractive index.

As the low refractive index layer usable in the present invention, a low refractive index layer composed of a crosslinking of a fluorine-containing resin which is crosslinked by heat or ionizing radiation (hereinafter also referred to as "fluorine-containing resin before crosslinking"), Or a low refractive index layer having voids inside the fine particles or the like is used by using fine particles and a binder polymer. The low refractive index layer applicable to the present invention is a low refractive index layer mainly using fine particles and a binder polymer . Particularly, in the case of a low refractive index layer (also referred to as a hollow fine particle) having a void in the inside of the particle, the refractive index can be further lowered, which is preferable. However, when the refractive index of the low refractive index layer is low, it is preferable because the antireflection performance becomes good, but it is difficult from the viewpoint of imparting strength to the low refractive index layer. For this balance, the refractive index of the low refractive index layer is preferably 1.45 or less, more preferably 1.30 to 1.50, further preferably 1.35 to 1.49, and particularly preferably 1.35 to 1.45.

The method of preparing the low refractive index layer may be appropriately used in combination.

The fluorine-containing resin prior to crosslinking is preferably a fluorine-containing copolymer formed from a fluorine-containing vinyl monomer and a monomer for imparting a crosslinkable group. Specific examples of the fluorine-containing vinyl monomer unit include, for example, fluoroolefins (e.g., fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, 1,2-dimethyl-1,3-dioxol), partially or completely fluorinated alkyl ester derivatives of (meth) acrylic acid (for example, bisquat 6FM (Osaka Organic Chemicals) or M-2020 Keen products), etc.), and fully or partially fluorinated vinyl ethers. Examples of the monomer for imparting a crosslinkable group include crosslinking groups such as glycidyl methacrylate, vinyltrimethoxysilane,? -Methacryloyloxypropyltrimethoxysilane, and vinyl glycidyl ether, (Meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate and the like having a carboxyl group, a hydroxyl group, an amino group and a sulfonic acid group in addition to the vinyl monomer having a functional group Allyl acrylate, hydroxyalkyl vinyl ether, hydroxyalkyl aryl ether, etc.). In the latter, it is possible to introduce a crosslinking structure by adding a compound having a group which reacts with a functional group in the polymer and another reactive group, after the copolymerization, in JP-A-10-25388 and JP-A-10-147739 . Examples of the crosslinkable group include acryloyl, methacryloyl, isocyanate, epoxy, aziridine, oxazoline, aldehyde, carbonyl, hydrazine, carboxyl, methylol and active methylene group. When the fluorine-containing copolymer is crosslinked by heating in combination with a crosslinking group which reacts by heating, or a combination of an ethylenic unsaturated group and a thermal radical generator or an epoxy group and a thermal acid generator, it is thermosetting, When the crosslinking is carried out by irradiation of light (preferably ultraviolet ray, electron beam or the like) by combination of an unsaturated group and a photo radical generator or an epoxy group and a photoacid generator, it is an ionizing radiation curable type.

In addition to the above monomers, a fluorine-containing copolymer formed by using a fluorine-containing vinyl monomer and a monomer other than a monomer for imparting a crosslinkable group may be used as the fluorine-containing resin before crosslinking. Examples of the monomer that can be used in combination include, but are not limited to, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylates (methyl acrylate, methyl acrylate, ethyl acrylate, Methacrylic acid esters (such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and ethylene glycol dimethacrylate), styrene derivatives (such as styrene, divinylbenzene, vinyltoluene, Vinyl ethers such as methyl vinyl ether and the like, vinyl esters such as vinyl acetate, vinyl propionate and vinyl cinnamate, acrylamides such as N-tertbutylacrylamide and N-cyclohexyl acrylamide, , Acrylonitrile derivatives, and the like. It is also preferable to introduce a polyorganosiloxane skeleton or a perfluoropolyether skeleton in order to impart slipperiness and antifouling property to the fluorine-containing copolymer. This is because, for example, polymerization of the above monomers with polyorganosiloxane or perfluoropolyether having an acryl group, a methacryl group, a vinyl ether group, a styryl group, or the like at the terminal thereof, a polymerization of a polyorganosiloxane having a radical generator at the terminal Polymerization of the above monomer with perfluoropolyether, reaction of a polyorganosiloxane or perfluoropolyether having a functional group with a fluorine-containing copolymer, and the like.

The proportion of each of the monomers used for forming the fluorine-containing copolymer before crosslinking is preferably 20 to 70 mol%, more preferably 40 to 70 mol%, and the amount of the crosslinkable group Is preferably 1 to 20 mol%, more preferably 5 to 20 mol%, and the other monomers used are preferably 10 to 70 mol%, and more preferably 10 to 50 mol%.

The fluorine-containing copolymer can be obtained by polymerizing these monomers in the presence of a radical polymerization initiator by means of solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization or the like.

The fluorine-containing resin before crosslinking is commercially available and can be used. Examples of commercially available fluorine-containing resins prior to crosslinking include commercially available fluorine-containing resins such as Cyot Top (product of Asahi Glass), Teflon (registered trademark) AF (DuPont), polyvinylidene fluoride, Lumiflon (Asahi Glass) JSR products).

The low refractive index layer comprising a crosslinked fluorine-containing resin as a constituent preferably has a coefficient of dynamic friction in the range of 0.03 to 0.15 and a contact angle to water in the range of 90 to 120 °.

It is preferable that the low refractive index layer comprising the crosslinked fluorine-containing resin as a constituent contains inorganic particles to be described later from the viewpoint of adjusting the refractive index. It is also preferable that the inorganic fine particles are subjected to a surface treatment. The surface treatment includes physical surface treatment such as plasma discharge treatment and corona discharge treatment, and chemical surface treatment using a coupling agent. The use of a coupling agent is preferable. As the coupling agent, an organoalkoxy metal compound (e.g., titanium coupling agent, silane coupling agent, etc.) is preferably used. When the inorganic fine particles are silica, treatment with a silane coupling agent is particularly effective.

Various sol-gel materials may also be used as the material for the low refractive index layer. As such a sol-gel material, metal alcoholates (alcoholates such as silane, titanium, aluminum and zirconium), organoalkoxy metal compounds and hydrolyzates thereof can be used. In particular, alkoxysilanes, organoalkoxysilanes and hydrolyzates thereof are preferred. Examples thereof include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, etc.), alkyltrialkoxysilane (methyltrimethoxysilane, ethyltrimethoxysilane, etc.), aryltrialkoxysilane (phenyltrimethoxysilane Etc.), dialkyldialkoxysilane, diaryldialkoxysilane, and the like. Further, an organoalkoxysilane having various functional groups (vinyltrialkoxysilane, methylvinyldialkoxysilane,? -Glycidyloxypropyltrialkoxysilane,? -Glycidyloxypropylmethyldialkoxysilane,? - (3, 4-epoxy dicyclohexyl) ethyl trialkoxysilane,? -Methacryloyloxypropyltrialkoxysilane,? -Aminopropyltrialkoxysilane,? -Mercaptopropyltrialkoxysilane,? -Chloropropyltrialkoxysilane, etc.) , A perfluoroalkyl group-containing silane compound (for example, heptadecafluoro-1,1,2,2-tetradecyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc.) It is also preferable to use it. Particularly, it is preferable to use a fluorine-containing silane compound from the viewpoint of lowering the refractive index of the layer and imparting water repellency and oil repellency.

As the low refractive index layer, it is also preferable to use inorganic or organic fine particles and use a layer formed as fine voids in the fine particles or in the fine particles. The average particle diameter of the fine particles is preferably from 0.5 to 200 nm, more preferably from 1 to 100 nm, even more preferably from 3 to 70 nm, most preferably from 5 to 40 nm. It is preferable that the particle diameters of the fine particles are as uniform as possible (monodispersed).

The inorganic fine particles are preferably amorphous. The inorganic fine particles are preferably composed of an oxide, a nitride, a sulfide or a halide of a metal, more preferably a metal oxide or a metal halide, most preferably a metal oxide or a metal fluoride. The metal reactant may be at least one selected from the group consisting of Na, K, Mg, Ca, Ba, Al, Zn, Fe, Cu, Ti, Sn, In, W, Y, Sb, Mn, Ga, V, Nb, Ta, Ag, Bi, Mo, Ce, Cd, Be, Pb and Ni are preferable, and Mg, Ca, B and Si are more preferable. An inorganic compound containing two kinds of metals may be used. Specific examples of the preferable inorganic compound are SiO ₂ or MgF ₂ , particularly preferably SiO ₂ .

The particles having micro voids in the inorganic fine particles can be formed, for example, by cross-linking molecules of silica forming the particles. When the molecules of silica are crosslinked, the volume is reduced and the particles become porous. The (porous) inorganic fine particles having micro voids may be formed by a sol-gel method (Japanese Patent Laid-Open No. 53-112732, Japanese Patent Publication No. 57-9051) or a precipitation method (APPLIED OPTICS, vol. 27, p. 3356 ) Can be directly synthesized as a dispersion. In addition, the powder obtained by the drying and precipitation method may be mechanically pulverized to obtain a dispersion. Commercially available porous inorganic fine particles (for example, SiO ₂ sol) may be used.

These inorganic fine particles are preferably dispersed in a suitable medium for the formation of the low refractive index layer. As the dispersion medium, water, an alcohol (for example, methanol, ethanol, isopropyl alcohol) and a ketone (for example, methyl ethyl ketone, methyl isobutyl ketone) are preferable.

The organic fine particles are also preferably amorphous. The organic fine particles are preferably polymer fine particles synthesized by a polymerization reaction of monomers (for example, emulsion polymerization method). The polymer of the organic fine particles preferably contains a fluorine atom. The proportion of fluorine atoms in the polymer is preferably 35 to 80 mass%, more preferably 45 to 75 mass%. It is also preferable to form micropores in the organic fine particles by, for example, crosslinking the polymer forming the particles to reduce the volume. In order to crosslink the polymer forming the particles, it is preferable that 20 mol% or more of the monomer for synthesizing the polymer is a polyfunctional monomer. The ratio of the polyfunctional monomer is more preferably 30 to 80 mol%, and most preferably 35 to 50 mol%. Examples of the monomers used for synthesizing the organic fine particles include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetra Fluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), fluorinated alkyl esters of acrylic acid or methacrylic acid, and fluorinated vinyl ethers. A copolymer of a monomer containing a fluorine atom and a monomer containing no fluorine atom may be used. Examples of the monomer containing no fluorine atom include olefins (e.g., ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic esters (e.g., methyl acrylate, ethyl acrylate, Hexyl), methacrylic acid esters (e.g., methyl methacrylate, ethyl methacrylate, butyl methacrylate), styrenes (e.g., styrene, vinyltoluene, alpha -methylstyrene), vinyl ethers (For example, methyl vinyl ether), vinyl esters (e.g., vinyl acetate, vinyl propionate), acrylamides (e.g., N-tert-butyl acrylamide, N-cyclohexyl acrylamide) Acrylamides, acrylamides, acrylamides, acrylamides and acrylamides. Examples of the polyfunctional monomer include dienes (e.g., butadiene, pentadiene), esters of polyhydric alcohols with acrylic acid (e.g., ethylene glycol diacrylate, 1,4-cyclohexane diacrylate, dipenta (For example, ethylene glycol dimethacrylate, 1,2,4-cyclohexanetetra methacrylate, pentaerythritol tetramethacrylate), polyglycidyl methacrylate, There may be mentioned divinyl compounds (for example, divinylcyclohexane, 1,4-divinylbenzene), divinylsulfone, bisacrylamides (for example, methylenebisacrylamide) and bismethacrylamides .

The microvoids between the particles can be formed by stacking at least two or more microparticles. Further, when spherical fine particles having the same particle size (complete monodisperse) are packed and filled, fine interstitial microvoids having a porosity of 26 vol% are formed. When the spherical fine particles having the same particle diameter are simply cubically charged, micropores between the fine particles having a porosity of 48% by volume are formed. In the actual low refractive index layer, since the distribution of the particle size of the fine particles and the micro voids in the particle are present, the porosity varies considerably from the above theoretical value. When the porosity is increased, the refractive index of the low refractive index layer is lowered. When fine particles are stacked to form micro voids, the particle size of the fine particles can be adjusted so that the size of the inter-particle micro voids can be easily adjusted to a suitable value (no scattering of light and no problem in the strength of the low refractive index layer) have. By making the particle diameters of the fine particles uniform, it is possible to obtain an optically uniform low refractive index layer having uniform inter-particle micro voids. Thus, although the low refractive index layer is microscopically a porous film containing micropores, it can be optically or macroscopically homogeneous. It is preferable that the inter-particle micro voids are closed in the low refractive index layer by the fine particles and the polymer. The closed pores have an advantage in that scattering of light on the surface of the low refractive index layer is less than that of the openings on the surface of the low refractive index layer.

By forming micro voids, the macropores of the low refractive index layer become lower than the sum of the refractive indexes of the components constituting the low refractive index layer. The refractive index of the layer is the sum of the refractive indices per volume of the constituent elements of the layer. The refractive index of the constituent components of the low refractive index layer such as the fine particles and the polymer is greater than 1, while the refractive index of air is 1.00. Therefore, by forming the minute voids, a low refractive index layer with a very low refractive index can be obtained.

In the present invention, it is also preferable to use hollow fine particles of SiO ₂ .

The hollow fine particles referred to in the present invention are particles having a particle wall and the inside thereof being hollow. For example, SiO ₂ particles having micro voids in the above-mentioned fine particles may be mixed with an organic silicon compound (alkoxysilanes such as tetraethoxysilane ) To cover the surface of the pore and block the pore opening. Or the cavity inside the particle wall may be filled with a solvent or a gas. For example, in the case of air, the refractive index of hollow fine particles can be remarkably lowered compared with ordinary silica (refractive index = 1.46) (refractive index = 1.44 To 1.34). By adding such hollow SiO ₂ fine particles, the refractive index of the low refractive index layer can be further reduced.

The preparation method of hollowing the particles having micro voids in the inorganic microfine particle may be carried out according to the method described in Japanese Patent Laid-Open Nos. 2001-167637 and 2001-233611, A commercially available hollow SiO ₂ fine particle may be used. Specific examples of commercially available particles include P-4 produced by Shokubai Chemical Industry Co., Ltd.

The low refractive index layer preferably contains a polymer in an amount of 5 to 50 mass%. The polymer has a function of adhering fine particles and maintaining the structure of the low refractive index layer including vacancies. The amount of the polymer used is adjusted so that the strength of the low refractive index layer can be maintained without filling the gap. The amount of the polymer is preferably 10 to 30 mass% of the total amount of the low refractive index layer. In order to adhere the fine particles to the polymer, it is necessary to (1) bind the polymer to the surface treatment agent of the fine particles, (2) form a polymer shell around the fine particles as a core, or . The polymer to be bonded to the surface treatment agent of the (1) is preferably a shell polymer of (2) or a binder polymer of (3). (2) is preferably formed by polymerization reaction around the fine particles before preparation of the coating liquid for the low refractive index layer. (3) is preferably formed by adding a monomer to the coating liquid of the low refractive index layer and simultaneously or simultaneously with the application of the low refractive index layer or by polymerization reaction. It is preferable to carry out the combination of two or all of the above-mentioned (1) to (3), particularly preferably a combination of (1) and (3) or all combinations of (1) to (3). (1) surface treatment, (2) shell and (3) binder will be described in this order.

(1) Surface treatment

The fine particles (particularly, the inorganic fine particles) are preferably subjected to a surface treatment to improve the affinity with the polymer. The surface treatment can be classified into a physical surface treatment such as a plasma discharge treatment or a corona discharge treatment, and a chemical surface treatment using a coupling agent. It is preferable to carry out only the chemical surface treatment or a combination of the physical surface treatment and the chemical surface treatment. As the coupling agent, an organoalkoxy metal compound (e.g., titanium coupling agent, silane coupling agent) is preferably used. When the fine particles are made of SiO ₂ , the surface treatment with the silane coupling agent can be particularly effectively performed. As a specific example of the silane coupling agent, the silane coupling agent described above is preferably used.

The surface treatment with the coupling agent can be carried out by adding a coupling agent to the dispersion of the fine particles and leaving the dispersion at room temperature to 60 占 폚 for several hours to ten days. In order to accelerate the surface treatment reaction, it is preferable to use an inorganic acid (e.g., sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, , Polyglutamic acid) or a salt thereof (e.g., metal salt, ammonium salt) may be added to the dispersion.

(2) Shell

The polymer forming the shell is preferably a polymer having a saturated hydrocarbon as a main chain. A polymer containing a fluorine atom in the main chain or side chain is preferable, and a polymer containing a fluorine atom in the side chain is more preferable. Polyacrylic acid esters or polymethacrylic acid esters are preferable, and esters of fluorine-substituted alcohol with polyacrylic acid or polymethacrylic acid are most preferable. The refractive index of the shell polymer decreases with an increase in the content of fluorine atoms in the polymer. In order to lower the refractive index of the low refractive index layer, the shell polymer preferably contains 35 to 80 mass% of fluorine atoms, more preferably 45 to 75 mass% of fluorine atoms. The polymer containing a fluorine atom is preferably synthesized by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom. Examples of the ethylenically unsaturated monomer containing a fluorine atom include fluoroolefins (e.g., fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl- 1,3-dioxol), fluorinated vinyl ethers, and esters of fluorine-substituted alcohol with acrylic acid or methacrylic acid.

The polymer forming the shell may be a copolymer composed of a repeating unit containing a fluorine atom and a repeating unit not containing a fluorine atom. The repeating unit not containing a fluorine atom is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer containing no fluorine atom. Examples of the ethylenically unsaturated monomer not containing a fluorine atom include olefins (e.g., ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic esters (e.g., methyl acrylate, ethyl acrylate, Ethylhexyl), methacrylic acid esters (e.g., methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate), styrene and derivatives thereof (e.g., styrene, divinylbenzene Vinyl acetate, vinyl propionate, vinyl cinnamate), acrylamide (for example, N-tert-butylstyrene, vinyltoluene and? -Methylstyrene), vinyl ethers Butyl acrylamide, N-cyclohexyl acrylamide), methacrylamide, and acrylonitrile.

When a binder polymer of (3) described later is used in combination, a shell polymer and a binder polymer may be chemically bonded by crosslinking by introducing a crosslinkable functional group into the shell polymer. The shell polymer may have crystallinity. When the glass transition temperature (Tg) of the shell polymer is higher than the temperature at the time of formation of the low refractive index layer, it is easy to maintain the micro voids in the low refractive index layer. However, when the Tg is higher than the temperature at the time of forming the low refractive index layer, the fine particles are not fused and the low refractive index layer is not formed as a continuous layer (as a result, the strength is lowered). In that case, it is preferable to use a binder polymer of the following (3) in combination and form the low refractive index layer as a continuous layer by the binder polymer. A polymer shell is formed around the fine particles to obtain core shell fine particles. The core shell fine particles preferably contain 5 to 90% by volume of the core composed of the inorganic fine particles, more preferably 15 to 80% by volume. Two or more kinds of core shell fine particles may be used in combination. In addition, shell-free inorganic fine particles and core shell particles may be used in combination.

(3) Binders

The binder polymer is preferably a polymer having a saturated hydrocarbon or polyether as a main chain, and more preferably a polymer having a saturated hydrocarbon as a main chain. The binder polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as a main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups. Examples of the monomer having two or more ethylenically unsaturated groups include esters of a polyhydric alcohol and (meth) acrylic acid (e.g., ethylene glycol di (meth) acrylate, 1,4-dicyclohexane diacrylate, (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, (Meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives (E.g., 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone Acrylamide (for example, methylene bisacrylamide) and methacrylamide. The polymer having a polyether as a main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, the crosslinking structure may be introduced into the binder polymer by the reaction of the crosslinking group. Examples of the crosslinkable functional group include an isocyanate group, an epoxy group, an aziridine group, an oxazoline group, an aldehyde group, a carbonyl group, a hydrazine group, a carboxyl group, a methylol group and an active methylene group. Vinyl sulfonic acid, acid anhydride, cyanoacrylate derivatives, melamine, etherified methylol, ester and urethane may also be used as monomers for introducing the crosslinked structure. As the block isocyanate group, a functional group exhibiting crosslinkability as a result of the decomposition reaction may be used. The crosslinking group is not limited to the above-mentioned compounds but may be one which shows reactivity as a result of decomposition of the functional group. As the polymerization initiator used in the polymerization reaction and crosslinking reaction of the binder polymer, a thermal polymerization initiator or a photopolymerization initiator is used, but a photopolymerization initiator is more preferable. Examples of the photopolymerization initiator include at least one compound selected from the group consisting of acetophenones, benzoins, benzophenones, phosphinoxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxide compounds, 2,3- Disulfide compounds, fluoroamine compounds, and aromatic sulfoniums. Examples of acetophenones are 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl- Morpholino propiophenone and 2-benzyl-2-dimethylamine-1- (4-morpholinophenyl) -butanone. Examples of the benzoin include benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. Examples of benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. An example of phosphine oxides is 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

It is preferable that the binder polymer is formed by adding a monomer to the coating liquid of the low refractive index layer, and simultaneously or after coating with the low refractive index layer, by polymerization reaction (further crosslinking reaction, if necessary). (For example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethylacrylate, diacetylcellulose, triacetylcellulose, nitrocellulose, polyester, alkyd Resin) may be added.

In addition, it is preferable to add a lubricant to the low refractive index layer or the other refractive index layer of the present invention, and the scratch resistance can be improved by imparting slipperiness. As the lubricant, a silicone oil or a waxy substance is preferably used. For example, a compound represented by the following formula is preferable.

R ₁ COR ₂

In the formula, R represents a saturated or unsaturated aliphatic hydrocarbon group having 12 or more carbon atoms. An alkyl group or an alkenyl group is preferable, and an alkyl group or alkenyl group having 16 or more carbon atoms is preferable. R ₂ represents a group -OM 1 (M 1 represents an alkali metal such as Na or K), -OH group, -NH ₂ group or -OR ₃ group (R represents a saturated or unsaturated aliphatic hydrocarbon group having 12 or more carbon atoms, Represents an alkyl group or an alkenyl group), and as R ₂ , a -OH group, -NH ₂ group or -OR ₃ group is preferable. Concretely, carnauba wax, beeswax, and montan wax, which contain a higher fatty acid or derivative thereof such as behenic acid, stearic acid amide, pentacosan or the like and a natural product thereof in large amounts, are also preferably used. Polyorganosiloxanes disclosed in Japanese Patent Publication No. 53-292, higher fatty acid amides disclosed in U.S. Patent No. 4,275,146, Japanese Patent Publication No. 58-33541, British Patent No. 927,446, Higher fatty acid esters (esters of a fatty acid having 10 to 24 carbon atoms and an alcohol having 10 to 24 carbon atoms) disclosed in JP-A-55-126238 and JP-A-58-90633, and U.S. Patent No. 3,933,516 A higher fatty acid metal salt disclosed in the specification, a polyester compound composed of a dicarboxylic acid having up to 10 carbon atoms and an aliphatic or cyclic aliphatic diol as disclosed in Japanese Patent Laid-Open Publication No. 51-37217, And dicarboxylic acid disclosed in the publication and oligopolyester from diol.

For example, the addition amount of the lubricant used in the low refractive index layer is preferably 0.01 mg / m ² to 10 mg / m ² .

The respective layers of the antireflection film or the coating liquid thereof may contain a polymerization inhibitor, a leveling agent, a thickening agent, a coloring inhibitor, an ultraviolet absorber, a silane coupling agent, an antistatic agent, An adhesive agent or an adhesive agent may be added.

Each layer of the antireflection film is coated by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method or an extrusion coating method (US Patent No. 2,681,294) As shown in FIG. Two or more layers may be simultaneously applied. The simultaneous coating method is disclosed in U.S. Patent No. 2,761,791, U.S. Patent No. 2,941,898, U.S. Patent No. 3,508,947, U.S. Patent No. 3,526,528, and Harazaki Yuji, coating engineering, page 253, Asakura Bookstore (1973) .

In the present invention, in the production of the antireflection film, it is preferable that the coating liquid is dried at 60 ° C or higher, preferably at 80 ° C or higher, when the coating liquid prepared is coated on a support and then dried. The drying is preferably performed at a dew point of 20 ° C or lower, and more preferably at 15 ° C or lower. It is also preferable that drying is started within 10 seconds after application to the support, and combining with the above conditions is a preferable production method for obtaining the effects of the present invention.

The cellulose ester optical film of the present invention is preferably used for a polarizing plate protective film, an antireflection film, a hard coat film, an anti-glare film, a retardation film, an optical compensation film, an antistatic film and a brightness enhancement film.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the examples, &quot; part &quot; or &quot;% &quot; is based on mass unless otherwise specified.

Example 1

[Preparation of cellulose ester optical film]

As the cellulose ester CE-1, 100 parts by mass of cellulose acetate propionate (acetyl group substitution degree = 1.92, propionyl substitution degree = 0.74, total degree of substitution = 2.66, weight average molecular weight = 220,000 (in terms of polystyrene) , 8 parts by mass of the polymer AMP-1 of the above (a), 2 parts by mass of KA-61 as a plasticizer, 0.25 parts by mass of the above I-16 (commercially available as Sumilizer GS (Sumitomo Chemical Co., Ltd.)) as a carbon radical scavenger (Commercially available as Irganox 1010 (available from Ciba Specialty Chemicals Co., Ltd.) as the phenol compound P-1, pentaerythritol tetrakis [3- (3,5-di-tert- butyl-4-hydroxyphenyl) propionate] ) As a phosphonite compound PN-1, 0.5 part by mass of tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'biphenylene diphosphonite (commercially available as GSY- (Manufactured by Sakai Chemical Industry Co., Ltd.)) and 0.25 parts by mass of 2- (2H-benzotriazol-2-yl) -6- (Commercially available as TINUVIN 928 (manufactured by Ciba Specialty Chemicals)) as fine particles (Matte) M-1, (Average primary particle size: 16 mu m) (commercially available as Aerosil R972V (Japan Aerosil Co., Ltd.)) were mixed and dried under reduced pressure at 60 DEG C for 5 hours. This cellulose acylate composition was melt-mixed at 235 DEG C using a biaxial extruder and pelletized. At this time, in order to suppress the heat generation due to the shearing at the time of kneading, a kneading disk was not used but an all screw type screw was used. Vacuumization was carried out from the vent hole, and the volatile component generated during kneading was removed by suction. Further, between the feeder and hopper to be fed to the extruder and the cooling bath from the extruder die, a dry nitrogen gas atmosphere was provided to prevent the moisture absorption of the resin.

The film-forming was carried out by the production apparatus shown in Fig.

The first cooling roll and the second cooling roll were made of stainless steel having a diameter of 40 cm, and the surface thereof was hard chrome plated. In addition, the roll surface temperature was controlled by circulating oil for temperature adjustment inside. The elastic touch roll had a diameter of 20 cm, the inner and outer tubes were made of stainless steel, and the surface of the outer tube was hard chrome plated. The thickness of the outer tube was 2 mm, and the surface temperature of the elastic touch roll was controlled by circulating oil for temperature adjustment in a space between the inner tube and the outer tube.

The resulting pellets (moisture content: 50 ppm) were cast from a T-die in the form of a film on a first cooling roll having a surface temperature of 130 占 폚 at a melt temperature of 250 占 폚 in the form of a film at a melt extrusion draw ratio of 20 using a single screw extruder. At this time, a T-die having a lip clearance of 1.5 mm and an average lip surface roughness Ra of 0.1 mu m was used. However, it represents the value obtained by dividing the lip clearance of the drawblanket die by the average film thickness of the flexible-cooled solidified film.

Further, on the first cooling roll, the film was pressed with an elastic touch roll having a metal surface of 2 mm thickness at a linear pressure of 10 kg / cm. The film temperature at the touch roll side at the time of pressing was 180 DEG C +/- 1 DEG C (here, the film temperature at the touch roll side at the time of pressing was the temperature of the film at the contact position of the touch roll on the first roll (cooling roll) Indicates the average value of the film surface temperature measured at 10 points in the width direction from the position spaced apart by 50 cm in the absence of the touch roll by retracting the touch roll). The glass transition temperature (Tg) of this film was 136 DEG C. (Glass transition temperature of the film extruded from the die by the DSC method (nitrogen, temperature elevation temperature 10 degrees / minute) using DSC6200 manufactured by Seiko Co., Respectively.

The surface temperature of the elastic touch roll was set at 130 占 폚, and the surface temperature of the second cooling roll was set at 100 占 폚. The surface temperature of each roll of the elastic touch roll, the first cooling roll, and the second cooling roll was set such that the temperature of the roll surface at a position 90 degrees ahead of the rotation direction from the position where the film firstly contacts the roll was measured using a non- Direction was taken as the surface temperature of each roll.

The obtained film was stretched by 1.05 times in the longitudinal direction by heating at 160 占 폚 by roll stretching, and subsequently stretched by a preheating zone, a stretching zone, a holding zone and a cooling zone (between the respective bands, a neutral band ), Stretched 1.20 times in the transverse direction at 160 DEG C, cooled to 70 DEG C while being relaxed by 2% in the transverse direction, and then opened with a clip to cut and cut the clip grip, A cellulose ester optical film F-1 having a film thickness of 80 mu m, Ro of 3 nm and Rt of 44 nm was produced by knurling a film having a width of 1030 mm and a height of 5 mu m at both ends of the film. At this time, the preheating temperature and the holding temperature were adjusted to prevent the boiling phenomenon by stretching.

Likewise, the optical films F-2 to 44 were produced under the conditions shown in Table 1 and Table 2 under the production conditions.

Details of the compound used and the production conditions are shown below.

The addition amount represents a part by mass relative to 100 parts by mass of the cellulose ester.

(Cellulose ester)

CE-2: cellulose acetate propionate, acetyl substitution degree = 1.41, propionyl substitution degree = 1.32, total degree of substitution = 2.73, weight average molecular weight = 220,000 (in terms of polystyrene)

CE-3: cellulose acetate propionate, acetyl group substitution degree = 1.38, propionyl substitution degree = 1.30, total substitution degree = 2.68, weight average molecular weight = 21,000 (in terms of polystyrene)

CE-4: Cellulose acetate propionate, acetyl substitution degree = 1.31, propionyl substitution degree = 1.23, total degree of substitution = 2.54, weight average molecular weight = 200,000 (polystyrene reduced)

In the above, the term "dispersion degree" means weight average molecular weight / number average molecular weight.

CE-5: Cellulose acetate propionate, acetyl substitution degree = 0.08, propionyl substitution degree = 2.75, total degree of substitution = 2.83, weight average molecular weight = 260,000 (polystyrene reduced)

CE-6: Cellulose acetate butyrate, acetyl substitution degree = 2.10, butyryl substitution degree = 0.73, total substitution degree = 2.83, weight average molecular weight = 23,000 (in terms of polystyrene)

CE-7: Cellulose acetate butyrate, acetyl substitution degree = 1.05, butyryl substitution degree = 1.78, total substitution degree = 2.83, weight average molecular weight = 28,000 (in terms of polystyrene)

(Polymer of (a) above)

(Synthesis Example 1)

A copolymer (AMP-1) of the exemplified compound AM-1 and methyl methacrylate was synthesized according to the method described below.

To 100 ml of toluene, 2.0 g of a commercially available example compound AM-1 and 8.0 g of methyl methacrylate were added, followed by 0.1 g of azoisobutyronitrile. And the mixture was heated to 80 DEG C in a nitrogen atmosphere and reacted for 5 hours. 70 ml of toluene was distilled off under reduced pressure, and the residue was added dropwise to a large excess of methanol. The deposited precipitate was filtered and vacuum-dried at 40 degrees to obtain 6.5 g of a copolymer (AMP-1). This copolymer was confirmed to have a weight average molecular weight of 25,000 and an Mw / Mn of 2.8 by GPC analysis based on standard polystyrene.

NMR spectrum, it was confirmed that the copolymer was a copolymer of Exemplified Compound AM-1 and methyl methacrylate. The composition of the polymer was approximately AM-1: methyl methacrylate = 20: 80.

Polymers AMP-2 to 25 of (a) were synthesized in the same manner as in Synthesis Example 1 except that the monomers described in Table 3 were used. The weight average molecular weight and the composition of the synthesized polymer were determined in the same manner as in Synthesis Example 1. [ Comparative polymers AMP-26 to 28 were synthesized in the same manner as in Synthesis Example 1, except that the monomers described in Table 3 were used as a comparison. Table 3 shows the details of the synthesized polymer.

(Phenolic compound)

P-2: Ethylene bis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate] (commercially available as IRGANOX-245 from Ciba Specialty Chemicals)

P-3: hexamethylene bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (commercially available as IRGANOX-259 from Ciba Specialty Chemicals)

P-4: octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (commercially available IRGANOX-1076 from Ciba Specialty Chemicals)

(Phosphorus compound)

PH-1: Compound

PH-2: Compound

(Ultraviolet absorber)

UV-2: The following compounds

UV-3: The following compounds

(Fine particles)

M-2: AEROSIL NAX50 (manufactured by Nippon Aerosil Co., Ltd.)

M-3: SEAHOSTAR KE-P100 (manufactured by Nihon Shokubai Co., Ltd.)

[Evaluation of cellulose ester optical film]

The samples prepared as described above were evaluated as described below. The results are shown in Tables 4 and 5.

(1) Evaluation of coloring at the end portion in the width direction (the ratio of the end portion and the yellow index YI in the middle portion)

In the production of the cellulose ester optical film, a sample 30 mm square from the both ends in the width direction of the cellulose ester film immediately after melt extrusion and a sample 30 mm square from the center of the film were cut out, and a spectrophotometer U-3310 manufactured by Hitachi High Technologies Inc. was used And the absorption spectrum thereof was measured to calculate tristimulus values X, Y and Z. [ Based on JIS-K7103, the yellow index Ye at the both ends of the film and the yellow index Yc at the center of the film were calculated from the tristimulus values X, Y, and Z, and the ratio Ye / Yc was calculated. In addition, the yellow index read the portion of the portion that becomes the maximum in the cut-out sample. The ratio of the yellow index at the end portion and the center portion was found to be 50 in each film, and the evaluation was made based on the following evaluation criteria based on the average value.

7: Ye / Yc is less than 1.2, which is a practically excellent level.

6: Ye / Yc is 1.2 or more and less than 1.5, which is a practically excellent level.

5: Ye / Yc is 1.5 or more and less than 3.0, practically no problem level.

4: Ye / Yc is 3.0 or more and less than 5.0, practically the lowest acceptable range.

3: Ye / Yc is 5.0 or more and less than 7.0, which is a level at which a problem may occur in practical use.

2: Ye / Yc is 7.0 or more and less than 10.0, which is a level at which practical problems arise.

1: Ye / Yc is 10.0 or more, which is a level at which a problem occurs in practical use.

(2) Evaluation of retardation distribution

The distribution of the retardation was determined by obtaining the coefficient of variation (CV) shown below.

The refractive indices of the prepared cellulose ester optical film samples in the three-dimensional direction were measured at intervals of 1 cm in the width direction. Plane retardation (Ro), retardation (Rt) in the thickness direction and coefficient of variation (CV) obtained from the following formulas were determined.

The measurement was carried out at a wavelength of 590 nm under an environment of 23 ° C and 55% RH using an automatic birefringence system KOBURA 21ADH (Prince Instruments Co., Ltd.), and the measured values were expressed by the following equations (a) and (b) Plane retardation (Ro) and thickness direction retardation (Rt) were calculated.

&Lt; Formula (a) >

Plane retardation (Ro) = (nx-ny) xd

&Lt; Formula (b) >

The retardation in the thickness direction (Rt) = ((nx + ny) / 2-nz) xd

Here, d is the thickness (nm) of the film, nx is the maximum refractive index in the plane of the film, and the refractive index in the slow axis direction. ny is the refractive index in the direction perpendicular to the slow axis in the film plane, and nz is the refractive index of the film in the thickness direction. The standard deviation of the obtained retardation in the thickness direction was determined by the (n-1) method. The coefficient of variation (CV) of the retardation in the thickness direction was obtained from the following formula. and n was set at 130 to 140.

(CV) of retardation (thickness direction) = standard deviation of retardation (Rt) / average value of retardation (Rt)

The retardation distribution was evaluated from the variation coefficient (CV) of the obtained retardation (Rt) in the thickness direction by the following evaluation criteria.

7: (CV) is less than 1.5%, which is a very good level in practice.

6: (CV) is 1.5% or more and less than 2.0%, which is a practically excellent level.

5: (CV) is not less than 2.0% and less than 5.0%, and practically no problem level.

4: CV (CV) is 5.0% or more and less than 6.0%, which is the practical minimum acceptable range.

3: (CV) is 6.0% or more and less than 8.0%, which is a level at which practical problems may occur.

2: CV (CV) is more than 8.0%, less than 10%, and there is a possibility of causing a practical problem.

1: CV (CV) is 10% or more, which causes a problem in practical use.

(3) Evaluation of foreign objects

Bright spot foreign matter is placed a film sample prepared between the two polarizers arranged in orthogonal (Cross-Nicol), reflecting the light from the outer side of one polarizing plate, white and diameter than 0.01mm per 25mm ² under a microscope from the outside of the other polarizer The number of empty foreign objects (spot foreign objects) was measured at 100 places, converted to a value when the thickness of the film was converted into 80 mu m, and the average value was expressed. The condition of the microscope at this time was a transmission light source at a magnification of 30 times. The smaller the number of spots, the better.

From Table 4 and Table 5, it can be seen that the sample of the present invention is an optical film having a small variation in the retardation in the width direction of the sample of the comparative example, suppressing the generation of foreign matter, It has been confirmed that it has excellent performance. That is, it has become clear that the combination of the polymer of (a) with a carbon radical scavenger, a phenol compound or a phosphorus compound brings about a preferable synergistic effect and improves the performance. It has also become clear that by containing three kinds of compounds at specific ratios, more excellent effects are exhibited.

Example 2

[Preparation of antireflection film and polarizing plate]

Using the optical films F-1 to 3, 5 to 8, 10 to 12, 14 to 18, 20 to 22, 24 to 27, 29 to 31 and 33 to 44 prepared in Example 1, A coat layer and an antireflection layer were formed to prepare an antireflection film with a hard coat. Using this, a polarizing plate was produced.

<Hard coat layer>

The following hard coat layer composition was applied to give a dry film thickness of 3.5 탆 and dried at 80 캜 for 1 minute. Next, a hard coat film having a hard coat layer was prepared by curing under a condition of 150 mJ / cm ^{2 with} a high-pressure mercury lamp (80W). The refractive index of the hard coat layer was 1.50.

&Lt; Hard coat layer composition (C-1) >

Dipentaerythritol hexaacrylate (containing about 2% of the dimeric or more components) 108 parts by mass

2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.)

180 parts by mass of propylene glycol monomethyl ether

120 parts by mass of ethyl acetate

<Medium Refractive Index Layer>

On the hard coat layer of the hard coat film, the following refractive index layer composition was applied by an extrusion coater and dried for 1 minute at 80 占 폚 and 0.1 m / sec. At this time, a non-contact plotter was used until the end of touched-up drying (a state in which the coated surface was felt to be dried by touching with a finger). As a non-contact plotter, a horizontal plotter type air tamper manufactured by BELMATIC CORPORATION was used. The static pressure in the floater was 9.8 kPa, and was floated uniformly in the width direction of about 2 mm and transported. After drying, ultraviolet rays were irradiated at 130 mJ / cm ² using a high-pressure mercury lamp (80 W) and cured to prepare a medium refractive index layer film having a medium refractive index layer. Among them, the thickness of the medium refractive index layer of the refractive index layer film was 84 nm, and the refractive index was 1.66.

<Medium refractive index layer composition>

20% ITO fine particle dispersion (average particle diameter 70 nm, isopropyl alcohol solution) 100 g

6.4 g of dipentaerythritol hexaacrylate

Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 1.6 g

Tetrabutoxy titanium 4.Og

10% FZ-2207 (propylene glycol monomethyl ether solution, manufactured by Japan Unicax Co., Ltd.) 3.0 g

Isopropyl alcohol 530 g

90 g of methyl ethyl ketone

265 g of propylene glycol monomethyl ether

&Lt; High refractive index layer &

The following high refractive index layer composition was coated on the medium refractive index layer with an extrusion coater and dried at 80 DEG C and 0.1 m / sec for 1 minute. At this time, a non-contact plotter was used until the end of touched-up drying (a state in which the coated surface was felt to be dried by touching with a finger). The non-contact plotter was subjected to the same conditions as the formation of the medium refractive index layer. After drying, ultraviolet rays were irradiated at 130 mJ / cm ² using a high-pressure mercury lamp (80 W) and cured to prepare a high refractive index layer film having a high refractive index layer.

&Lt; High refractive index layer composition >

95 parts by mass of tetra (n) butoxytitanium

1 part by mass of dimethylpolysiloxane (KF-96-1000CS from Shin-Etsu Chemical Co., Ltd.)

γ-methacryloxypropyltrimethoxysilane (KBM503, Shin-Etsu Chemical Co., Ltd.)

                                                      5 parts by mass

1750 parts by mass of propylene glycol monomethyl ether

Isopropyl alcohol 3450 parts by mass

600 parts by mass of methyl ethyl ketone

The thickness of the high refractive index layer of this high refractive index layer film was 50 m and the refractive index was 1.82.

<Low Refractive Index Layer>

First, silica-based fine particles (hollow particles) were prepared.

(Preparation of silica-based fine particles S-1)

A mixture of 100 g of silica sol having an average particle diameter of 5 nm and an SiO ₂ concentration of 20% by mass and 1900 g of pure water was heated to 80 캜. The pH of this reaction mother liquor was 10.5, 9000 g of sodium silicate aqueous solution of 0.98 mass% as SiO ₂ and 9000 g of sodium aluminate aqueous solution of 1.02 mass% as Al ₂ O ₃ were simultaneously added to the mother liquor. In the meantime, the temperature of the reaction solution was maintained at 80 캜. The pH of the reaction solution rose to 12.5 immediately after the addition and thereafter hardly changed. After completion of the addition, the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO ₂ · Al ₂ O ₃ core particle dispersion having a solid content concentration of 20 mass% (Step (a)).

By applying a pure 1700g on a nuclear particle dispersion 500g heated to 98 ℃ and, while maintaining this temperature, a silicate solution obtained by de-alkali to aqueous solution of sodium silicate with a cation exchange resin was added (SiO ₂ concentration of 3.5% by weight) 3000g first To obtain a dispersion of nuclear particles having a silica coating layer formed thereon. (Process (b)) [

Next, 1125 g of pure water was added to 500 g of the nuclear particle dispersion liquid in which the first silica coating layer having a solid content concentration of 13% by mass was removed by washing with an ultrafiltration membrane, and hydrochloric acid (35.5% . Next, the aluminum salt dissolved in the ultrafiltration membrane was separated by adding 10 L of a hydrochloric acid aqueous solution having a pH of 3 and 5 L of pure water, and a part of constituent components of the nuclear particles having the first silica coating layer formed was removed to prepare a SiO ₂ · Al ₂ O ₃ porous particle (Step (c)). A mixed solution of 1500 g of the porous particle dispersion, 500 g of pure water, 1,750 g of ethanol and 626 g of 28% ammonia water was heated to 35 ° C, and 104 g of ethyl silicate (28% by mass of SiO ₂ ) Was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer. Next, a dispersion of silica-based fine particles having a solid content concentration of 20% by mass obtained by replacing the solvent with ethanol using an ultrafiltration membrane was prepared.

Table 6 shows the thickness, average particle diameter, MO x / SiO ₂ (molar ratio), and refractive index of the first silica coating layer of the silica-based fine particles. Here, the average particle diameter was measured by a dynamic light scattering method, and the refractive index was measured using CARGILL JEAN series A and AA as a standard refractive solution by the following method.

&Lt; Method of measuring refractive index of particles >

(1) The dispersion of particles is placed in an evaporator, and the dispersion medium is evaporated.

(2) Dry it at 120 캜 to obtain a powder.

(3) Drop a standard refraction solution already known with a refractive index on a 2 or 3 drop glass plate, and mix the powder with the above.

(4) The operation of the above (3) is performed with various standard refraction liquids, and the refractive index of the standard refraction liquid when the mixed liquid becomes transparent is referred to as the refractive index of the colloid particles.

(Formation of low refractive index layer)

Si (OC ₂ H ₅₎ to _{95mol% 4, C 3 F 7} - (OC 3 F 6) 24 -O- (CF 2) 2 -C 2 H 4 -0-CH 2 Si (0CH 3) ₃ to 5mol % Of the above silica-based fine particles S-1 having an average particle diameter of 60 nm was added to the matrix to prepare a low refractive index coating agent diluted with a solvent using 1.O N-HCl as a catalyst. The coating solution was coated on the active ray hardened resin layer or the high refractive index layer by a die coating method to a film thickness of 100 nm and dried at 120 degrees for 1 minute and then irradiated with ultraviolet rays to form a low refractive index layer having a refractive index of 1.37 .

Thus, an antireflection film was produced using the cellulose ester optical film prepared in Example 1. [

Next, the polyvinyl alcohol film having a thickness of 120 탆 was uniaxially stretched (temperature 110 캜, stretching magnification 5 times). This was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and then immersed in an aqueous solution of 68 DEG C consisting of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizing film.

Next, the polarizing film, the antireflection film and the cellulose ester film on the back side were bonded according to the following steps 1 to 5 to prepare a polarizing plate. A commercially available cellulose ester film, Konica Minolta Tact KC8UCR-4 (manufactured by Konica Minolta Opto Co., Ltd.) was used as a polarizing plate for the polarizing plate protective film on the back side.

Step 1: The film was immersed in a 2 mol / L sodium hydroxide solution at 60 占 폚 for 90 seconds, followed by washing with water and drying to obtain the antireflection film which was saponified on the side to be bonded with the polarizer.

Step 2: The polarizing membrane was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2 mass% for 1 to 2 seconds.

Step 3: In step 2, excess glue adhered to the polarizing film was lightly wiped off, and this was laminated on the optical film treated in step 1.

Step 4: The antireflection film sample laminated in Step 3, the polarizing film and the cellulose ester film were bonded at a pressure of 20 to 30 N / cm ² and a conveying speed of about 2 m / min.

Step 5: A sample obtained by bonding the polarizing film prepared in Step 4 and the cellulose ester film to the antireflection film in a dryer at 80 캜 was dried for 2 minutes to prepare a polarizing plate.

[Production of liquid crystal display device]

A liquid crystal panel for performing the viewing angle measurement was manufactured as follows, and the characteristics as a liquid crystal display device were evaluated.

The polarizing plates on both sides of the 15-inch display VL-150SD manufactured by Fujitsu Ltd. were peeled off, and the polarizing plates thus fabricated were each bonded to the glass surface of the liquid crystal cell.

At that time, the polarizing plate was bonded in such a manner that the surface of the antireflection film was the observation surface side of the liquid crystal, and the absorption axis was directed in the same direction as the previously polarized polarizing plate, thereby manufacturing liquid crystal display devices.

The antireflection film produced by using the optical film of the present invention exhibited unevenness in hardness and less line unevenness, and the polarizing plate and liquid crystal display device using the same showed no problem of reflected color irregularity, and exhibited excellent display contrast. The antireflection films produced using the samples compared in Example 1 had unevenness in hardness and line irregularities, and the result was that the polarizing plate and liquid crystal display device using the same produced reflection color unevenness.

Example 3

[Preparation of Antistatic Film and Polarizer]

Using the optical films F-1 to 3, 5 to 8, 10 to 12, 14 to 18, 20 to 22, 24 to 27, 29 to 31 and 33 to 44 prepared in Example 1, A coat layer and an antistatic layer were formed to prepare an antistatic film having a hard coat. Using this, a polarizing plate was produced.

(Coating composition)

(Antistatic layer coating composition)

Polymethyl methacrylate (weight average molecular weight 550,000, Tg: 90 DEG C) 0.5 part

Propylene glycol monomethyl ether 60 parts

Methyl ethyl ketone 16 parts

Ethyl lactate 5 parts

Methanol 8 parts

Conductive polymer resin CP-1 (0.1 to 0.3 mu m particle) 0.5 part

(Hard coat layer coating composition)

Dipentaerythritol hexaacrylate monomer 60 parts

Dipentaerythritol hexaacrylate dimer 20 parts

20 parts of dipentaerythritol hexaacrylate trimer or higher component

Diethoxybenzophenone photoinitiator 6 parts

One part of silicone surfactant

Propylene glycol monomethyl ether 75 parts

Methyl ethyl ketone 75 parts

(Anti-curl layer coating composition)

Acetone 35 parts

Ethyl acetate 45 parts

Isopropyl alcohol 5 parts

0.5 part of diacetylcellulose

Ultrafine Silica 2% Acetone Dispersion (Aerosil 200 V) (manufactured by Japan Aerosil Co., Ltd.) 0.1 part

An antistatic film having a hard coat was produced as follows.

On one side of the cellulose ester optical film sample prepared in Example 1, a curl preventing layer coating composition was gravure coated so as to have a wet film thickness of 13 占 퐉 and dried at a drying temperature of 80 占 占 폚. On the other side of this cellulose ester optical film, an antistatic layer coating composition was applied at a film transporting speed of 30 m / min at a coating width of 1 m so as to have a wet film thickness of 7 탆 at an environment of 28 캜 and 82% RH, Lt; 0 &gt; C and dried to form a resin layer having a dry thickness of about 0.2 mu m to prepare an antistatic film.

Further, after onto the antistatic layer is formed so that 13μm of the hard coat layer coating composition (2) to a wet film thickness, dried at a drying temperature 90 ℃, is irradiated to the ultraviolet light is 150mJ / m ^2, a dry film thickness A clear hard coat layer of 5 mu m was provided. The obtained optical film did not cause brushing, and cracking after drying was not recognized, so that the coating property was good.

All of the inventive samples prepared in Example 1 were found to have good applicability. The antistatic film produced using the sample compared in Example 1 was brushed when applied in a high humidity environment. In addition, fine cracks were recognized after drying.

Next, a polarizing plate using the antistatic film was prepared in the same manner as in Example 2. [

[Production of liquid crystal display device]

A liquid crystal panel for performing the viewing angle measurement was manufactured as follows, and the characteristics as a liquid crystal display device were evaluated.

The polarizers on both sides of the 15-type display VL-150SD made by Fujitsu Ltd. were peeled off, and the polarizing plates thus prepared were bonded to the glass surface of the liquid crystal cell, respectively.

At that time, the polarizing plates were bonded in such a manner that the surface of the antistatic film faced the observation side of the liquid crystal, and the absorption axis was directed in the same direction as the previously polarized polarizing plate, thereby producing liquid crystal display devices The display characteristics were evaluated.

The liquid crystal display using the polarizing plate using the antistatic film produced from the cellulose ester optical film of the present invention showed a high contrast and a superior display property as compared with the liquid crystal display using the polarizing plate produced using the sample compared in Example 1 . Thus, it was confirmed that the polarizing plate using the optical film of the present invention is excellent as a polarizing plate for an image display apparatus such as a liquid crystal display.

Example 4

[Polarizing plate, production of liquid crystal display device]

The retardation films F-4, 9, 13, 19, 23 and 28 prepared in Example 1 were used in place of the Konica Minolta Tact KC8UCR-4 (Konica Minolta Opto Co., Ltd.) , 32 were used and the polarizing plate protective film on the front side was changed to Konica Minolta Tact KC8UX (manufactured by Konica Minolta Opto), and a polarizing plate and a liquid crystal display device were produced in the same manner as in Example 2, And the polarizing plate and the liquid crystal display device using the cellulose ester optical film of the present invention did not have a problem of reflected color unevenness and exhibited excellent display contrast.

According to the present invention, it is possible to provide a cellulose ester optical film which has excellent optical properties such as a small deviation of retardation in the width direction, suppresses the generation of foreign objects, and is less colored at the end portions in the film width direction, A polarizing plate and a liquid crystal display using a film, and a method capable of producing these cellulose ester optical films by a method of reducing the production load, equipment load and environmental load accompanying drying and recovery of a solvent.

Claims (18)

A cellulose ester optical film characterized by containing a cellulose ester satisfying the substitution degree of the following formulas 1 to 3, a polymer (a), a compound (b1), and a compound (b2) <Formula 1> 2.4? A + B? 3.0 <Formula 2> 0? A? 2.4 <Formula 3> 0.1? B <3.0 (Wherein A represents the substitution degree of the acetyl group and B represents the sum of the degree of substitution of the acyl group having 3 to 5 carbon atoms) (a): a polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the following formula (1) and at least one ethylenically unsaturated monomer in a molecule &Lt; Formula 1 >

(Wherein, R ^1, R ² and R ³ are each independently an aliphatic group which may have a substituent, represents a heterocyclic group which may have an aromatic group, or a substituent which may have a substituent, and, R ^1, R ^2, and Any two of R &lt; ³ &gt; may be bonded to each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded) (b1): at least one carbon radical scavenger selected from the group consisting of compounds represented by the following general formulas (2) and (3) (2)

(Wherein R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ¹² and R ¹³ each independently represent an alkyl group having 1 to 8 carbon atoms) (3)

(Wherein R ²² to R ²⁵ each independently represent a hydrogen atom or an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and R ²⁶ represents a hydrogen atom or a substituent , An aromatic group which may have a substituent, or a heterocyclic group which may have a substituent, n represents 1 or 2, and when n is 1, R ²¹ represents an aliphatic group which may have a substituent , An aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and when n is 2, R ²¹ represents a divalent linking group. (b2): at least one compound selected from the group consisting of a phenol compound having a structure represented by the following formula (6) and a phosphonate compound represented by the following formula (4) or (5) (6)

(Wherein R ⁴¹ , R ⁴² and R ⁴³ represent an alkyl substituent which is further substituted or unsubstituted) &Lt; Formula 4 > R ³¹ P (OR ³² ) ₂ (Wherein R ³¹ represents a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² may combine with each other to form a ring) &Lt; Formula 5 > (R ³⁴ O) ₂ PR ³³ -R ³³ P (OR ³⁴ ) ₂ (Wherein R ³³ represents a phenylene group which may have a substituent or a thienylene group which may have a substituent, R ³⁴ represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, A plurality of R &lt; ³⁴ &gt; may combine with each other to form a ring) The method according to claim 1, Characterized in that the carbon radical scavenger is contained in the range of 0.1 to 1.0 part by mass, the phenolic compound is contained in the range of 0.2 to 2.0 parts by mass, and the phosphorus compound is contained in the range of 0.1 to 1.0 part by mass with respect to 100 parts by mass of the cellulose ester By weight based on the total weight of the cellulose ester optical film. 3. The method according to claim 1 or 2, Wherein the polymer of (a) has a weight average molecular weight of 1,000 or more and 70,000 or less. 3. The method according to claim 1 or 2, Wherein the ethylenically unsaturated monomer having a partial structure represented by the general formula (1) in the molecule is N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylpiperidone, N-vinylcaprolactam, or a mixture thereof Characterized by a cellulose ester optical film. 3. The method according to claim 1 or 2, Wherein R ³⁴ in the general formula (5) is a substituted phenyl group having a substituent having a total of 9 to 14 carbon atoms relative to one phenyl group (provided that a plurality of substituents within a range of the total number of carbon atoms in a phenyl group is 9 to 14) Wherein the cellulose ester optical film is a cellulose ester film. 6. The method of claim 5, Wherein the phosphonate compound represented by Formula 5 is tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene diphosphonite. 3. The method according to claim 1 or 2, A cellulose ester optical film characterized by containing at least one ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid. 3. The method according to claim 1 or 2, A cellulose ester optical film characterized by containing at least one ultraviolet absorber. 3. The method according to claim 1 or 2, A cellulose ester optical film characterized by containing at least one fine particle. A polarizing plate characterized by using the cellulose ester optical film according to claim 1. A liquid crystal display device characterized by using the cellulose ester optical film according to claim 1 or the polarizing plate according to claim 10. A cellulose film comprising a cellulose ester satisfying the substitution degree of the following formulas (1) to (3), a polymer comprising the following polymer (a), a compound represented by the following formula (b1) and a compound represented by the following formula A method for producing an ester optical film. <Formula 1> 2.4? A + B? 3.0 <Formula 2> 0? A? 2.4 <Formula 3> 0.1? B <3.0 (Wherein A represents the substitution degree of the acetyl group and B represents the sum of the degree of substitution of the acyl group having 3 to 5 carbon atoms) (a): a polymer obtained by copolymerizing an ethylenically unsaturated monomer having a partial structure represented by the following formula (1) in the molecule with at least one ethylenic unsaturated monomer &Lt; Formula 1 >

(Wherein, R ^1, R ² and R ³ are each independently an aliphatic group which may have a substituent, represents a heterocyclic group which may have an aromatic group, or a substituent which may have a substituent, and, R ^1, R ^2, and Any two of R &lt; ³ &gt; may be bonded to each other to form a cyclic structure together with a nitrogen atom or a nitrogen atom and a carbon atom to which they are bonded) (b1): at least one carbon radical scavenger selected from the group consisting of compounds represented by the following general formulas (2) and (3) (2)

(Wherein R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ¹² and R ¹³ each independently represent an alkyl group having 1 to 8 carbon atoms) (3)

(Wherein R ²² to R ²⁵ each independently represent a hydrogen atom or an aliphatic group which may have a substituent, an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and R ²⁶ represents a hydrogen atom or a substituent , An aromatic group which may have a substituent, or a heterocyclic group which may have a substituent, n represents 1 or 2, and when n is 1, R ²¹ represents an aliphatic group which may have a substituent , An aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and when n is 2, R ²¹ represents a divalent linking group. (b2): at least one compound selected from the group consisting of a phenol compound having a structure represented by the following formula (6) and a phosphonate compound represented by the following formula (4) or (5) (6)

(Wherein R ⁴¹ , R ⁴² and R ⁴³ represent an alkyl substituent which is further substituted or unsubstituted) &Lt; Formula 4 > R ³¹ P (OR ³² ) ₂ (Wherein R ³¹ represents a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, R ³² may combine with each other to form a ring) &Lt; Formula 5 > (R ³⁴ O) ₂ PR ³³ -R ³³ P (OR ³⁴ ) ₂ (Wherein R ³³ represents a phenylene group which may have a substituent or a thienylene group which may have a substituent, R ³⁴ represents an alkyl group which may have a substituent, a phenyl group which may have a substituent or a thienyl group which may have a substituent, A plurality of R &lt; ³⁴ &gt; may combine with each other to form a ring) 13. The method of claim 12, Wherein the yellow index (Yc) at the center of the film after melt extrusion and the yellow index (Ye) at the end of the film satisfy the following formula (4). <Formula 4> 1.0? Ye / Yc? 5.0 The method according to claim 12 or 13, And stretching the cellulose ester film after melt extrusion in 1.0 to 4.0 times in one direction and 1.01 to 4.0 times in the direction orthogonal thereto. delete delete delete delete

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